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2-Stroke Fuel Mix Calculator

Enter gasoline volume and pick 25:1, 40:1, 50:1 or a custom ratio to get exact oil in ml for chainsaws and trimmers.

3D Printer Filament Cost Calculator

Pick PLA, ABS, PETG or TPU preset, switch length or weight input, and get material cost plus spool remaining.

A11y Tap Target Size Checker

Pick a device and dimensions, check Pass/Fail across WCAG 2.2 AA/AAA, Apple HIG and Android Material in real mm.

WCAG Contrast Ratio Checker

Compute WCAG 2.x luminance ratio between text and background HEX and judge AA, AAA, normal and large-text thresholds.

A4 Window Envelope Fold Guide

Mark tri-fold lines and window position for A4 letters going into Japanese Nagagata-3 window envelopes, export as PNG.

ABV Calculator

Get the alcohol by volume of your brew (simple and advanced formulas) plus apparent attenuation from original and final gravity, for OG 1.000 to 1.170.

Research Paper Title Generator

Enter 2+ research keywords. Get 5 academic compound titles with colon structures, each rated by an impact score 75-98%.

Age Calculator

Break a birthdate into years, months, and days, or pick a future date to count down to a due date or anniversary.

Agri Spray Rate Calculator

Compute spray volume in L/ha, gal/acre or L/10a from nozzle flow, boom width and speed, and back-solve target speed.

AI Prompt PII Masker

Mask email, IPv4, URL, JP phone, マイナンバー and card numbers in LLM prompts locally. Restoration map generated alongside.

AI Prompt Weight Visualizer

Parse (word:1.2), ((word)) and [word] in Stable Diffusion prompts and chart each token weight as a normalized bar.

SD1.5 / SDXL Bucket Distribution Checker

Visualize LoRA dataset balance across SD 1.5 (512px) and SDXL (1024px) buckets via log-AR distance — copy-ready summary, no signup.

Aim Trainer

Browser aim trainer with Static and Tracking modes. Live score, accuracy, average reaction (ms) and FPS readout.

Airsoft LiPo Battery Discharge & Fuse Safety Calculator

Get max LiPo discharge from mAh × C, compare against the fuse, and receive 15/20/25/30A and SBD/FET advice.

Alcohol Clearance Calculator

Estimate alcohol metabolism from weight, volume and ABV. Pure alcohol grams plus full clearance time, not a legal BAC.

Allergen Icon Sheet Builder

Tick the 8 allergens of Japan Food Labeling Act (egg, milk, wheat, soba, peanut, shrimp, crab, walnut) for 3x PNG.

Amazon FNSKU Code 128 Barcode Label Generator

Enter FNSKU, product name and 5 conditions to output a Code 128 FBA barcode label as a 600×360px PNG.

Amazon Mobile Search Result Mockup & Product Image Simulator

Drop your product plus 3 competitors to render an Amazon mobile SERP mockup at 400×840px, exported as 2x PNG.

ANSI 256 Color Picker

Click any cell in the ANSI 256 palette (16 system colors + 216 RGB cube + 24 grayscale) to copy \e[38;5;Nm, \e[48;5;Nm, bash and printf forms with hex.

Tenant Move-Out Cost Calculator (Japan)

Estimate tenant share for wallpaper or flooring under Japan's MLIT guideline with straight-line method and 1% residual.

API Response Time Percentile Calculator

Paste a list of response times to compute P50, P90, P95 and P99 percentiles plus mean, median, standard deviation and a distribution histogram.

App Icon Squircle Mask Previewer (iOS / Android / macOS)

Preview 1024px icons through iOS squircle, Android circle / squircle and macOS masks, then export 2048px retina PNG.

App Store Screenshot Safe Zone Checker

Overlay Dynamic Island, status bar and home indicator zones on 6.7" and 5.5" iPhone screenshots before submission.

Appliance L-Corridor Clearance Calculator

Sweep 1-89 degree angles to test if a fridge or washer fits an L-shaped hallway, with Canvas 2D collision animation.

Planted Aquarium CO2 Concentration Calculator

pH 5.5-8.5 and KH 1.0-20.0 dKH sliders compute CO2=3*KH*10^(7-pH) on a 0-60 mg/L bar; optimal 20-30, red alert above 30.

Aquarium Fish Stocking Capacity Calculator

Convert tank dimensions or volume to safe fish capacity via the 1cm=1L rule, with an 80/100% stocking progress bar.

Aquarium Heater Wattage and Cost Calculator

Heater wattage with 1.5x safety rounded to 19 retail sizes, plus monthly cost from tank volume and target temperature.

Aquarium Salt Bath and Medicine Dose Calculator

Estimate tank volume from dimensions, then compute salt grams from target % or scale label dose to your aquarium volume.

Aquarium Salt Mix Calculator

Set 1 to 500 L volume, pick SG or ppt target, and read grams for Red Sea, Coral Pro, Instant Ocean or generic mix.

Aquarium Water Change Calculator

Enter your tank volume and change rate to see the exact litres to replace and the water left behind. A 60L tank at 25% needs 15L, no guesswork.

Aquarium Water Temp Mixer

Calculate exact litres of tap water and hot water to mix for any bucket size and target aquarium temperature.

ASCII Art Text Generator

Turn short text into large ASCII art letters across seven FIGlet-style fonts like Banner, Block, Big, and Slant, then copy the result.

ASCII Table and Search

All 128 ASCII codes with Dec, Hex, HTML entity and control names. Type a char, number or NUL/ESC to filter live.

Aspect Ratio Calculator

Width-to-height ratio calculator: type one side, get the other. Five presets (16:9, 4:3, 1:1, 21:9, 2:3) plus custom.

Aspect Ratio Calculator

Get the GCD ratio from W×H, solve pixels from a ratio, or turn diagonal inches into real cm/inch. 21:9 monitor presets.

Aspect Ratio Calculator (Visual)

Visual aspect ratio tool that simplifies width and height to lowest terms, draws a rectangle preview, and reverse-solves sizes from 9 presets like 16:9.

CSS Aspect Ratio Padding Calculator

Turn any width:height ratio into the padding-top percentage for responsive boxes, with both the legacy position snippet and a modern aspect-ratio version.

Astro 500 Rule Calculator

Find the longest shutter speed that keeps stars as points with the 500 rule. Enter focal length and sensor crop factor to get seconds before star trails.

Audio Bit Depth Dynamic Range Calculator

Read PCM dynamic range, ideal SNR, LSB voltage and quantization noise from any 1-32 bit depth. One-tap presets cover CD, DAT, studio and 32-bit float.

Audio Buffer Latency Calculator

Turn a 64-2048 sample buffer and the sample rate into DAW latency in ms, with a sound-travel distance, 60fps frames, and a live/studio/offline verdict.

Comb Filter Notch Frequency Calculator

List the first six comb-filter notch and peak frequencies from a 0.02-50 ms delay slider, with sum and diff modes and the path difference in cm/inches.

Sound Pressure Level Distance Attenuation Calculator

Find the dB SPL at any target distance with point, line, and plane models, plus loss, pressure and intensity ratios and a 6-tier reference chart.

Equal-Loudness Contour SPL Calculator

Enter frequency (20-12500 Hz) and phon (20-90) to compute SPL on the ISO 226:2003 equal-loudness contour, with hearing threshold, alpha_f and Lu.

FFT Bin Frequency Resolution Calculator

Pick a sample rate and FFT size N to get bin resolution sr/N, Nyquist, the analysis window, usable bins, and cents per bin at 100 Hz, 1 kHz, and 10 kHz.

Audio File Size Estimator

Estimate file size and compression ratio across 10 formats (WAV, FLAC, MP3, AAC and more) from duration, sample rate, bit depth and channels.

Haas Effect Delay Calculator

Solve delay in ms from a 0-500 m path difference and -40 to 60 C temperature, then classify it as direct-fusion, Haas, or echo with cutoffs at 1 and 40 ms.

Streaming Platform LUFS Target Converter

Pick from 8 streaming and broadcast targets like Spotify -14 LUFS or EBU R128 -23 to read the dB gain offset and if the new true peak clears -1.0 dBTP.

Octave-Band Frequency Edges Calculator

Get lower/upper edges, bandwidth, and Q from a center frequency and a 1/1 to 1/24 octave fraction, plus the cents offset to the nearest ISO 266 center.

PCM Audio Buffer Size Calculator

Size WAV files and recording buffers from sample rate, bit depth, channels and duration, with buffer bytes, samples per channel, bitrate and byte rate.

Audio Quantization Noise & SNR Calculator

Set bit depth (1-32), dither (RPDF / TPDF / none) and signal level in dBFS to compute full-scale SNR, noise floor, dynamic range and quantization levels.

RT60 Reverberation Time Calculator (Sabine / Eyring)

RT60 reverberation time from both the Sabine and Eyring formulas. Volume, surface and absorption α set each value, plus the percentage gap on a 0-5 s bar.

Audio Sample Rate and Nyquist Calculator

From sample rate (4-192 kHz), bit depth, and channels, get the Nyquist frequency, dynamic range, PCM bitrate, and uncompressed file size across 9 presets.

Speaker Port Tuning Frequency Calculator (Bass-Reflex)

Get the bass-reflex tuning frequency Fb of a vented box. Helmholtz resonance with a 1.463·r end-correction effective length stays near the measured value.

Total Harmonic Distortion (THD) Calculator

Read THD-F (IEEE) next to THD-R (IEC 60268) from H1 and H2-H8 amplitudes, in percent, ppm and dB. SINAD and ENOB share the panel for ADC and DAC checks.

Avatar Initial Generator

Generate 1024×1024 profile PNGs from 1-4 initials. 3 shapes (circle, rounded, square) × 3 styles (solid, gradient, outline) — 9 looks, browser-only.

Award Certificate PNG Builder

Build A4 landscape 3508x2480 (300 DPI) award certificate PNGs with Gold, Navy, or Mono themes, decorative corners, and a central circular seal.

AWS SigV4 Canonical Request Builder

Build the AWS SigV4 Canonical Request with signed-headers, payload hash, and canonical-request SHA-256 on one screen to debug signature mismatch errors.

Badge Button Safe Zone Checker

Overlay safe zone, trim, and bleed guides on a circular badge image and export a 300 DPI PNG template for 25 to 75 mm pin-back button print orders.

Baker's Percentage Calculator

Computes baker's percentages from flour/liquid/other ingredients, highlights hydration and exports a 600px recipe PNG.

Baking Pan Recipe Scaler

Round, square, and rectangular pan sizes generate a base-area ratio that rescales each ingredient row automatically.

Bandwidth Transfer Time Calculator

Estimate how long a file takes to transfer from its size, link speed, and an overhead percentage, with auto unit conversion from B to TB and bps to Gbps.

Barbell Plate Loading Calculator

Find which plates to load per side from your target and bar weight, largest first. Covers standard kg and lb sizes with the achievable total and remainder.

Base58 Encoder & Decoder

Encode hex bytes into Bitcoin Base58 / Base58Check with 5 version-byte presets, and decode Base58 strings back to hex with a double-SHA-256 checksum verdict.

Base64 Encoder & Decoder

Convert text to and from Base64 with safe UTF-8 multibyte handling, ideal for Basic Auth headers and log triage.

Base64 File Converter

Convert files to Base64 and back, toggle the DataURI prefix, copy the first 1000 chars, set MIME manually.

Base64 Image Viewer

Paste a Base64 string to preview the image, or drop a file to get its code. Auto-detects format, size and dimensions.

Base64 URL-Safe Converter

Encode text to standard and URL-safe Base64 side by side, then decode either variant back to UTF-8, with optional padding strip and 76-char wrap.

Base85 Encoder / Decoder

Encode and decode text as Base85 in two variants: PDF/PostScript Ascii85 and ZeroMQ Z85, with invalid characters flagged inline as you type or paste.

Battery Discharge Time Calculator

Estimate how long a battery lasts from its mAh capacity and mA current draw, with a 50-100% efficiency slider, reverse capacity mode, and Wh conversion.

Battery Series-Parallel Calculator

Enter cell voltage, capacity and C-rate to get pack voltage, capacity, energy in Wh and max discharge current for series and parallel packs.

Bayes Theorem Calculator

See the posterior P(A|B) after a positive result. Tune prior, sensitivity, and false-positive rate from 0.01% to 99.99%, plus marginal P(B).

bcrypt Cost Factor Calculator

Benchmark bcrypt cost factors 4 through 15 directly on your own CPU, then pick the highest factor that still fits a target hash time such as 250 ms.

Bead Art Grid Generator

Convert images (max 128×128) into grid patterns for Perler beads, cross-stitch or diamond art. Ruler & coordinates, PNG.

Beer Line Length Calculator

Find the balanced beer line length that pours without foaming. Covers 5 tubing IDs with a PSI breakdown and a pour-speed check for lines too fast or slow.

Bellows Extension Exposure Compensation Calculator

Get the exact exposure compensation in stops for macro and large-format gear. A 100mm lens racked out 50mm needs +1.17 stops, with the exposure factor too.

Benham's Disk Online

Flick a Benham disk online and watch faint red, green and blue Fechner colors emerge from a black-and-white pattern.

Beta Distribution Probability Calculator

Evaluate any Beta(alpha, beta) distribution at a point x and read its density, cumulative probability, mean, variance, mode and standard deviation at once.

Bias Binding Calculator

Find how much continuous bias binding a square of fabric yields, or work backward from the length you need to the fabric size, based on your strip width.

Bicycle Chain Link Calculator

Calculate exact chain links from chainstay length, front/rear largest cogs and pulleys, with even round-up and Eagle +2.

Bicycle Gear Ratio & Speed Calculator

Calculate cycling gear ratio, m/rev and km/h from chainring, sprocket and cadence. Six tire presets included.

Weighted Bill Splitter

Set 0-3x weight sliders and 1/10/100/1000 rounding, then a greedy algorithm builds the minimum-transaction settlement.

Binary Text Converter

Convert UTF-8 text to and from binary, toggle 8-bit spacing, and view HEX side by side with a Matrix flicker.

Binomial Distribution Probability Calculator

Get the exact binomial P(X=k) plus cumulative and upper-tail probability, mean, variance and mode. Log-gamma math stays stable for n up to 1000.

Birthday Paradox Calculator

See the odds that two people in a group share a birthday, with the head count needed to reach 50, 95, and 99 percent. Group size 2 to 100, any day pool.

BMI Calculator

Compute Body Mass Index from height and weight instantly with WHO four-tier category and metric/imperial unit toggle.

Reverse BMI Calculator

Reverse weight from BMI with Japan's aesthetic presets (Standard 22, Aesthetic 20, Model 18) plus current-weight diff.

Visual BMI Calculator

Slide height and weight to compute BMI with a 6-tier color meter and a body silhouette that scales by index.

Bolt & Wrench Size Reference

Tap any JIS metric thread from M1 to M30 to read the matching wrench flat, pilot hole, and nut height.

Book Cover Spine Calculator

Calculate book spine width from page count and paper thickness, then preview the full wraparound cover spread with finished print size in millimeters.

Bookbinding Signature Calculator

Computes signatures, spine width, and weight from pages and thickness. ISO + Letter/Legal sizes, mm/in toggle.

Booklet Creep Calculator

Compute saddle-stitch creep per sheet from page count and paper thickness with imposition pages and outer/inner labels.

Bookmark Printable Sheet

Generate 2480×3508 PNG bookmark sheets on A4. Choose 4 or 6 per page, pick decor (line, dots, wave), set title + subtitle — print and cut at home.

Fancy Border Radius Generator

Sculpt blob and organic shapes with 8 horizontal and vertical border-radius sliders, then copy the CSS rule.

Box Breathing Guide

Pick Box 4-4-4-4 or 4-7-8, follow a scaling circle over 1/3/5 minute sessions with optional rain or wind procedural BGM.

Box Shadow Generator

Stack multiple shadow layers with X/Y offset, blur, spread, color, opacity and inset toggle, live preview included.

BPM Tapper

Tap a button or hit Space and the latest 12 taps average into a live BPM with a 6-tier music genre label.

BPM to Delay ms Calculator

Tempo to ms: enter BPM, get delay times for 15 note values plus LFO Hz, with a reverb pre-delay table for short notes.

Bra Size & Sister Size Calculator

Enter underbust and bust to get JP (5 cm), US (2-inch) and UK sizes plus sister size tips for tight or loose bands.

Braille Signage Layout Generator (JIS T 0921:2019)

Render Japanese braille plates per JIS T 0921:2019 with 1.5mm dots, 2.5mm spacing, 6x10mm cells and retina PNG.

Bread Hydration Calculator

Find the water a dough needs from flour weight and hydration (50-100%), minus moisture from eggs or milk, with baguette and ciabatta presets.

Breaker Panel Label Maker

Enter one label per line to fill an A4 landscape 5-column grid of 140×60px cells. Font shrinks 20-10px, PNG 2x export.

Mindful Breathing Circle

Set inhale 2-10s, hold 0-10s, exhale 2-10s and follow a synced expanding circle with cue text in fullscreen.

Brine Salt Ratio Calculator

Get the exact salt weight for any brine in grams. Set water volume and 0-30% ratio for pickles, fermentation, and curing, with teaspoon and total readouts.

Business Card Bleed Checker

Overlay bleed, trim line, and safe zone guides on JP 91×55mm, US, or EU business card sizes. Adjust bleed and margin from 1 to 10 mm and export a PNG.

Caffeine Residual & Sleep Impact Simulator

Pick a drink, weight, intake time and bedtime to compute residual caffeine and the safe last-intake time (5h half-life).

Calligraphy Slant Guide Maker

Set slant 30-85°, x-height, ascender and descender ratios, pick a line color and export a 2048x1536 transparent PNG for Copperplate practice.

Camera Memory Card Capacity Calculator

Calculate how many JPEG or RAW photos fit on a memory card from its capacity and file size, and estimate 4K or 1080p video recording time from the bitrate.

Candle Burn Time Estimator

Estimates hours from wax weight, type coefficient (paraffin/soy/beeswax/gel) and wick, with a calibration mode for g/h.

Cardboard Box Resizer Calculator

Enter width, depth and heights to compute corner slit depth and new girth, with a color-coded isometric SVG cut diagram.

Case Converter

Convert text to 9 cases at once: UPPER, lower, Title, Sentence, camelCase, snake_case, kebab-case, CONSTANT, dot.

Mixtape A/B Side Track Sequencer

Pick a tape spec from C-46 to C-120, paste tracks as MM:SS lines, the tool fills Side A and B, leftovers go to Overflow.

Cat Age Calculator

Enter your cat's age and see the human-year equivalent: 1y=15, 2y=24, then +4 human years per cat year.

CCTV Field of View Calculator

Enter sensor size, focal length, and subject distance to get horizontal and vertical angles plus a top-down SVG.

CCTV Recording Duration Calculator

Estimates bitrate, daily GB and days from 1-32 cams, 1080p/4K, 15/30 fps, H.264/H.265 and 1-16 TB HDD (90% usable).

Cents to Frequency Calculator

Convert between cents and frequency both ways: shift a base pitch like 440 Hz by a cents offset, or measure the cents gap between two frequencies.

ChaCha20-Poly1305 Nonce Reuse Validator

Paste ChaCha20-Poly1305 or XChaCha20 nonces to catch reuse, wrong lengths, and collision risk, plus the safe message count for 96- and 192-bit nonces.

Cheer Uchiwa Text Maker

Generates an A4 landscape 1123x794px stencil at jumbo size with 1-4 chars, 10 Google Fonts and outline as PNG.

Chess Board Diagram PNG Maker

Build a chess diagram (1200x1200 PNG) from a FEN or by clicking pieces onto the board. Classic / Wood / Mono themes, white/black flip, coords toggle.

Chi-Square Test Calculator

Compute the chi-square statistic, degrees of freedom, p-value, and critical value from observed and expected counts, with a verdict at 4 alpha levels.

chmod Calculator

Toggle Owner/Group/Public r/w/x and sync octal (755), symbolic (rwxr-xr-x) and chmod command both ways, with -R flag.

CHMOD Permission Grid

Click 9 owner/group/others × r/w/x cells; octal, symbolic and ls -l auto-sync, with a Security Risk warning on 777.

chmod Symbolic Converter (3-digit owner/group/other)

Convert chmod between numeric 755 and symbolic rwxr-xr-x for owner/group/other and copy ready chmod commands.

CIDR Range Overlap Checker

Compares every pair of IPv4 CIDR blocks to find where address ranges overlap, listing each conflicting IP range and host count for subnet and VPC planning.

Click Speed Test

Check click speed over 1, 5, 10 or 60 seconds. Get CPS, a 5-tier rank from god finger to sloth, and a 0.5s pace chart.

Clothing Measurement Diagram Maker

Overlay top or bottom garment measurements as guide lines and labels on a flat-lay photo, exported as 800x800 PNG.

CMYK Ink Limit and Rich Black Checker

Sums TIC at 250/300 thresholds and isolates Registration Black 400% from Rich Black so prepress files stay press-safe.

Cocktail Dilution Calculator

Estimate the final ABV, volume, and water added from each ingredient (volume + ABV), mixing method, and time.

Cocktail Recipe Scaler

Scale any cocktail recipe to the number of drinks you need. Add ingredient rows, switch ml and oz in one tap, and read the total batch volume.

Codebase to LLM Prompt Builder

Combine multiple source files into one Markdown block with directory tree. Paste straight into ChatGPT or Claude; binary files auto-skipped.

Coffee Roast Weight Loss Calculator

See the 12-20% roast weight loss for any home batch in one number. Enter green and roasted grams for the grams lost and a light, medium, or dark guide.

Pour-over Coffee Yield Calculator

Computes brew water from beans and ratio, splits bloom, first and final pour with cumulative volume and step delta.

Color Blindness Simulator

Apply protanopia, deuteranopia, tritanopia or achromatopsia filters to images, drag-split versus original, export PNG.

Color Contrast Checker (WCAG 2.1)

Check WCAG 2.1 contrast ratio between two colors with 6 AA/AAA pass-fail checks for normal text, large text, and UI.

HEX RGB HSL Color Converter

Three-way live conversion between HEX, RGB and HSL with instant sync across fields and a live color preview swatch.

Color Gradient Palette Maker

Build smooth gradients and stepped color palettes in seconds. Blend 2-5 colors, toggle linear or radial, set a 0-360 angle and 3-24 steps, then copy CSS.

Color Mixer

Online color mixer: blend two HEX via RGB lerp, generate 3/5/7/10-step gradient palettes, click any swatch to copy.

Color Shade & Tint Generator

Turn one base HEX color into 10 darker shades and 10 lighter tints, each with HEX and RGB values you can copy with a single click.

Commit Message Validator

Check commit messages against 8 Conventional Commits rules: type, 50/72-char subject, imperative mood, and footer — color-coded with a copyable report.

JIS Rebar Spacing Calculator (Japan D10-D22)

Calculate rebar quantity, length, and weight for Japan JIS D10-D22 deformed bars. Single or double layer supported.

Conference Badge Maker

Print-ready conference name badge from name, role, organization, event title, and accent color. Exports a 2100x1300 PNG.

Construction Site Digital Blackboard Generator

Type project name, work type, station and contractor, then export a green or black digital blackboard as a 1200x900 PNG.

Contrast Ratio Checker

Check color contrast ratio against WCAG 2.1 — AA/AAA pass/fail for normal and large text in real time.

Cookie Parser

Splits key=value pairs and URI-decodes them into an editable table; add or delete rows, re-serialize or export to JSON.

CORS Config Snippet Generator

Generates Nginx, Apache, Express and Go CORS snippets at once and warns when Origin=* is paired with credentials true.

Coupon PNG Generator

Build a 1200x600 PNG coupon image with scissor-cut dashed border in Crimson, Forest, or Royal themes, % or amount discount, promo code, and expiry.

CRC-32 / CRC-32C Checksum Calculator

Compute both the IEEE 802.3 CRC-32 and the Castagnoli CRC-32C from one text or hex input, shown side by side in hex and decimal with the byte length.

Crochet Circle Increase Calculator

Per-round stitch counts and 'work N then increase' steps for flat circles in single, half double or double crochet.

Cron Expression Generator

5-field cron expressions with a plain summary like "Every week, Monday, 00:00" beside the string, plus syntax checks for range, list, and */N steps.

Cron Expression Explainer & Next-Run Simulator

Translates 5-field cron into natural JA/EN/ES sentences and previews the next 5 run times with step, range, list syntax.

Cron Next Run Previewer

Type a cron expression to list the next 10 run times across 11 time zones, with the five fields broken out and a plain-language summary in one view.

Cross-Stitch Fabric and Thread Calculator

Enter stitches, fabric (11-32 ct), strands and margin to get finished cm, cut size and 8m skein count via 1.2 factor.

CSP Inline Hash Generator

Computes SHA-256 via Web Crypto API and emits the quoted 'sha256-...' Base64 token ready to paste into CSP directives.

CSS background-repeat Live Tiling Previewer

Upload an image and compare all six background-repeat values on a 500px canvas with drag-pan position and 10–400% zoom.

CSS border-image Slice Visualizer

Drag horizontal and vertical guides or type px values to set 9-slice points and preview stretch, repeat, round and fill.

CSS clamp() Generator

Enter min and max viewport widths and values to build a responsive CSS clamp() expression by linear interpolation, with a px/rem toggle and preview.

CSS clamp() Fluid Typography Generator

Computes rem+vw clamp() from min/max viewports and font sizes against a 16px base, plotting the curve on canvas.

CSS Filter Color Solver

Enter a hex; SPSA solves invert, sepia, saturate, hue-rotate, brightness and contrast to recolor a black icon.

CSS Media Query Generator

Generate responsive CSS @media rules, then refine them with min-width, max-width, or range breakpoints, device presets, and prefers-color-scheme.

CSS Named Color Lookup

Maps the 148 CSS named colors to hex, RGB, HSL, and OKLCH, and finds the nearest CSS name for any hex via OKLab ΔE distance with a swatch grid.

Cross-Browser Scrollbar CSS Generator

Tune width 2–30, radius 0–20 and three colors via sliders to output live ::-webkit-scrollbar and scrollbar-color CSS.

SVG Data URI Encoder

Encode SVG to a minimal percent-encoded data:image/svg+xml URI with paste-ready CSS url() snippet, base64 size comparison and fill color override.

CSS Triangle Generator

CSS triangle generator using the border-trick: 8 directions (4 cardinal + 4 diagonal) with width, height, color preview.

CSV to JSON Converter

Parses CSV with PapaParse 5.4.1, with toggles for header row and number/boolean type inference, auto-updating in 250ms.

CSV to Markdown Table Converter

Paste CSV and convert it to a GitHub-flavored Markdown table. Supports comma, tab, semicolon, and pipe delimiters plus an optional header row.

curl to fetch/axios Converter

Paste a curl command and convert it into JavaScript fetch or axios code. Reads method, headers, JSON body and auth flags, then toggles between both styles.

Cursive Text Generator (Mathematical Script)

Convert A–Z and a–z into Unicode Mathematical Script or Bold Script instantly, with one-click copy and bold toggle.

Curtain Hook Spacing Calculator

Enter fabric width and 4-30 hooks to get whole-inch spacing and balanced edge margins, previewed on a dot diagram.

Cycling Power Zone Calculator

Enter your FTP in watts and instantly see all 7 Coggan power zones (Z1 to Z7) with exact watt ranges, so you know the target output for each interval.

Damerau-Levenshtein Distance Calculator

Compute the Damerau-Levenshtein distance, similarity %, and normalized value for two strings, with an insert, delete, substitute, and transpose breakdown.

Data URI Converter

Convert any file to a Base64 Data URI and decode Data URIs back into files. Shows MIME type, file size and Base64 length, with inline preview for images.

Business Date Calculator

Find the date after N working days or count business days between two dates. Excludes weekends and custom holidays.

Date Difference Calculator

Counts days between two dates and also shows the gap broken down into weeks plus days, regardless of input order.

Decision Wheel

Spin a Canvas roulette with per-option weights 1-10, three-stage physics simulation and Web Audio tick and fanfare cues.

Density Altitude Calculator

Work out density altitude from pressure altitude and outside air temperature, plus the deviation from the ISA standard to gauge hot-day performance.

Depth of Field Visualizer

Pick full-frame, APS-C or M4/3 sensors with 10-600mm focal and f/1.0-22, then read hyperfocal and DOF on an 800x340 SVG.

dev.to Article Cover Image Maker

Build a dev.to article cover (1000x420 recommended) at 2000x840 PNG for retina quality. 4 accent colors, title, tag, author, download from the browser.

Bubble Level, Compass & 3D Cube (DeviceOrientation)

Reads alpha/beta/gamma to drive a 192px bubble level, a compass ring and a 3D cube live, with iOS permission flow.

Dice Probability Calculator

Calculate the sum probability distribution for N dice of M sides (2d6, 3d8, 4d20) and chart each total odds, min, max, mean and combination count.

Diceware Passphrase Entropy Calculator

Compare Diceware, EFF and BIP-39 passphrase strength across 4 word lists and 1-20 words: entropy bits, brute-force time, and a NIST 80-bit strength rank.

Character-Level Text Diff Checker

Paste original and edited text to see character-level changes highlighted live, with sync scroll and edit counters.

Digital Canvas Layer Limit Estimator

Predict how many layers your device can handle in Procreate, Photoshop or Clip Studio Paint. Adjust 2-32 GB RAM and 8/16-bit toggles — free, no signup.

Digital Square Seal Generator

Render a vermilion #E60012 square seal as a 1000px transparent PNG, with auto layout for 1-16+ characters and 10 fonts.

Directory Tree Generator

Build a folder tree for README from indented text or by dragging a real folder; .git and node_modules auto-collapse.

Discord Server Banner Maker

Generate Discord server banner PNGs at 1920×1080 (16:9). Set server name + tagline, choose 3 backgrounds (solid, gradient, grid) — Boost Level 2 required.

Discount Calculator

Computes sale price and savings from list price and percent off, with twin horizontal bars showing the cut visually.

Multi Discount and Tax Calculator

Stack multiple percentage and fixed-amount discounts in any order, add or strip sales tax, see the final price live.

DIY Concrete Calculator

Estimate concrete or mortar volume from project dimensions and get exact bag counts for cement, sand and gravel.

DIY Perfume Ratio Calculator

Enter volume, fragrance percentage and dropper size (0.05/0.04/0.03 ml) to get oil ml, drops and base ml instantly.

DIY Solar Charge Time Calculator

Estimates charge hours from battery Wh, panel W and a 5-step weather picker that derates the panel to effective watts.

DIY Stair Slope Calculator

From height, run, and step count, get riser, tread, and pitch angle with a Japanese residential-code check.

DIY Tile Layout & Offset Calculator

Optimal tile layout that equalizes left/right cuts from area, tile, grout widths and 1/2 or 1/3 shift mode, with view.

DMX Address DIP Switch Calculator

Convert any DMX address into a 9-switch DIP chart and binary, with 0-based and 1-based modes for any fixture brand.

TRPG Dice Roller

Rolls d4-d20 in parallel with +/- counters, modifier add, WebAudio dice clack, shake animation and last-20 roll history.

DNS Propagation TTL Calculator

See exactly when a changed DNS record finishes spreading worldwide. Built-in 5min, 1h, 24h and 48h TTL presets with a live remaining-time countdown — free.

Dog Age Calculator

Enter your dog's age in years to see the human-equivalent age. Quick insight into life stage and senior years.

Dog Food Gram Calculator

Enter dog weight, life-stage factor and food kcal per 100g to get daily energy needs (DER) and grams to feed.

Doujinshi Colophon Generator

Builds a 800x500 monochrome colophon PNG from title, date, author, contact and printer fields with optional R-18 badge.

Doujin Price Tag Maker

Build L-size 1050x1500 price tag POPs on Canvas with new/back issue badges and a QR slot, then export PNG.

Drop Rate Attempts Calculator

Find your odds of getting an item at least once. Shows the runs needed at 90/95/99% confidence, plus mean attempts and standard deviation on one screen.

Pregnancy Due Date Calculator

Estimate due date from your last menstrual period and cycle length, with current week and fetal size by fruit.

Dummy Data Generator

Build a custom schema row by row, generate up to 1,000 realistic records with faker.js v8, then preview and export them as JSON, CSV or SQL INSERT.

Duplicate Remover

Paste a newline list and remove duplicates instantly — strips blank lines and sorts A-Z or Z-A in one click.

Earthing Resistance Calculator

Grounding resistance from earthing class A/B/C/D, soil resistivity, electrode geometry; parallel electrodes if needed.

E-bike Range Estimator

Estimate e-bike range km and Wh/km from battery Wh or Ah times V, three assist tiers, rider weight and hill rate.

Ed25519 Signature Verifier

Paste a 32-byte Ed25519 public key, the message, and a 64-byte signature as hex, base64, or base64url. Browser Web Crypto runs RFC 8032 verification.

Electricity Cost Calculator

Kilowatt hour cost calculator: enter watts/kW, hours, and kWh price for live daily, monthly, and yearly costs.

Electricity Cost Calculator

6 appliance presets + custom rows (W × h/day) and kWh rate: daily, monthly, yearly cost with kWh consumption.

Email Header Analyzer

Paste a raw email header to read SPF, DKIM and DMARC results, the originating IP and every Received hop with relay delays. For spoofing and spam checks.

Email Subject Line Analyzer

Score subject lines 0-100 from length 20-50, power words, emoji, spam terms, with Positive/Neutral/Urgent/Spam label.

Embedding Vector Cosine Similarity Calculator

Compute cosine similarity, angle and distance between two numeric vectors in comma, space, or JSON format. Handles up to 4096 dims and shows norms.

Emergency Water Stockpile Calculator

Calculate emergency water stock, 2 L bottle count, and storage footprint from household size, pets, days, and climate.

Emojify Text Tool

Decorate posts by replacing or appending emojis to about 35 dictionary keywords with three density steps.

Japanese Era Converter

Convert between Western years and Japanese eras (Reiwa, Heisei, Showa, Taisho, Meiji) both ways with 元年 support.

ETag Weak / Strong Validator

Parse two HTTP ETags and apply the RFC 7232 strong and weak comparison rules to see whether a cache hit, Range request, or conditional request would match.

EV Charging Cost Simulator

Estimate DC fast-charge time and cost from kWh, SOC range, charger kW and per-minute rate via a 3-stage tapered curve.

EV Charging Time Calculator

Estimate how long an EV takes to charge from battery size, current and target charge level, and charger power. Shows energy, cost, and range added.

Booth Status Card Maker

Generate 800x560 booth status cards on Canvas from three presets: away, sold out, end of line, then save PNG.

Event Ticket Stub PNG Maker

Build perforated 1800x600 PNG event ticket stubs with Classic, Sunset, or Neon themes and a decorative QR-style block. For keepsakes and stream visuals.

EXIF Viewer and Eraser

Read all EXIF tags from JPG, PNG, WebP images, map GPS to Google Maps, and export a metadata-stripped JPEG.

F-Distribution Probability Calculator

Judge F-test significance fast: enter numerator df, denominator df 1-1000, and an F value for the PDF, CDF, and right-tail p-value plus a p<0.05 verdict.

Fabric Shrinkage Calculator

Calculate the required cut size, extra allowance, and total area from finished size, fabric type, and pre-wash status.

Factorial, Permutation and Combination Calculator

Enter n up to 1000 and an optional r to get n!, nPr and nCr as full BigInt integers, with the expansion formula shown.

Favicon Tab Simulator

Preview a PNG, ICO, SVG or URL favicon in Chrome, Safari, Firefox light and dark tabs and export the 4x zoom as PNG.

Bread Fermentation Timer

Estimate first/second rise times and water temp from dough type, target dough temp, and room temp via the Q10 rule.

File Hash Calculator

Pick MD5, SHA-1, SHA-256 or SHA-512, drop a file and paste an expected hash for auto-match. Streams 2MB chunks.

Film Developer Dilution Calculator

Enter a dilution ratio like 1+9 and your total working volume to get exactly how many mL of stock and water to mix, for any batch from 250 mL up.

Reel Backing Line Calculator

Enter spool capacity, main line, and backing diameter to get the exact backing length. lb/yd or mm/m units.

Flash Guide Number Calculator

Get the exact f-stop for manual flash from a GN of 36 in seconds. Distance, aperture and ISO are covered, with the nearest standard stop shown too.

Food Open-Date Storage Label Maker

Builds 600x400 labels with an 8px border from item, open date and shelf-life days and exports a 1200x800 Canvas2D PNG.

Secure HTML Form Autocomplete Attribute Builder

Pick the purpose of each input and get the HTML autocomplete attribute to guide browser autofill safely.

Fraction ↔ Decimal Converter

Convert decimals to fractions and back, with repeating decimal notation. Use to check math homework or simplify ratios.

FPS to MS Converter

Convert frames to ms at 60, 120, 144 or 240 FPS with slider 1-120 or numeric 1-999 input, copy-ready 'X.XX ms'.

Friendship Bracelet Thread Calculator

Compute floss cut lengths per strand for Flat, Diagonal, Chevron, and Spiral patterns with separate multipliers.

Homemade Fruit Liqueur ABV Estimator

Estimate final ABV and volume from base spirit, fruit and sugar. 60-80% moisture range plus 800×500px PNG recipe export.

Fuel Cost Calculator

Calculate trip fuel cost from distance, mileage, and price. Split between passengers, compare two cars, km/L or MPG.

Gacha Pull Probability Calculator

Returns the at-least-once chance, the pulls needed for a target percent, and the expected pulls to land one, from any rate between 0.001 and 100 percent.

Gamma Distribution Probability Calculator

Get the gamma PDF, CDF and survival at a point x for a given shape k and scale theta, with mean ktheta, variance, deviation and mode in one panel.

Gamma Function Stirling Approximation Calculator

Enter x (0.5-170) to compute Γ(x) via a 5-term Stirling series, plus log₁₀ Γ(x) and the relative gain the correction terms add over the leading term.

Ganache Ratio Calculator

Find the exact cream weight for 200g of chocolate in seconds. Covers dark, milk and white across 4 uses, from firm truffles to whipped ganache.

GCD & LCM Calculator

Calculate GCD and LCM for 3 or more numbers with step-by-step prime factorization, full divisor lists, and automatic Coprime detection — free, no signup.

Gemstone Carat Estimator

Estimate gemstone weight in carats from L×W×D dimensions, 11 stone types and 9 cut shapes. Certificate-style PNG export.

GIF Frame Delay Calculator

Convert between GIF frame delay in milliseconds and FPS, then read total playback duration and loops per minute from your frame count.

Gift Tag Generator

Generate gift tag PNGs at 1024×1024 instantly. Pick from 4 shapes (rectangle, rounded, heart, luggage) and 5 icons — free, browser-based, no signup.

Gift Wrap Size Calculator

Enter box width, depth, height and overlap to get the exact paper W×H for caramel wrap, with a scaled layout export.

Git Bisect Steps Calculator

Find how many git bisect steps locate a bug in N commits via ceil(log2(N)), estimate total time from your build duration, and see each binary halving.

Git Command Generator

Pick from six scenarios like undo commit or stash; dynamic form options build the matching command with explanation.

GitHub Actions cron JST to UTC Generator

Enter JST time and weekdays; outputs on.schedule cron YAML in UTC, shifting weekdays back when JST hours roll over.

GitHub Social Preview Card

Build a GitHub Open Graph card with owner/repo plus a tagline and language tag — 1280x640 PNG, Dark / Light / Accent themes, accent-color picker.

.gitignore Pattern Tester

Paste .gitignore patterns and paths to see which files are ignored or kept, tagged with the matched rule line. Handles negation (!), dir-only /, ** globs.

Glasses to Contacts Power Converter

Convert your glasses SPH prescription to equivalent contact lens power using vertex distance, rounded to 0.25 D steps.

Glitch Image Generator

Upload a photo and add RGB shift, slicing, noise, and scanlines. Seed-locked, hover to compare original.

Gmail 102KB HTML Size Checker

Paste HTML email source to gauge UTF-8 byte size against Gmail's 102KB clip with progress bar and overage alert.

Golf Club Distance Gap Calculator

From a reference club, carry yardage and Normal or Strong loft, derives 13 clubs and colors gaps at 15 and 10 yards.

Google Calendar Add-Event Link Generator

Generate an 'Add to Google Calendar' URL from event details so attendees open a prefilled event page from the link.

GPT Token Counter

Offline cl100k_base-style heuristic weighting CJK at 1.1 tok/char and English words by ceil(len/4) for instant counts.

Grout Quantity Calculator

Compute grout volume, weight, and bag count from tile size, joint width and depth, area, and grout density. The English version supports a Metric/US toggle: enter values in mm/m²/g·cm⁻³ with 1 kg & 5 kg bag results, or switch to in/ft²/lb·ft⁻³ with 5 lb & 25 lb bag results.

Guitar Capo Transposer

Set source and target key, paste a chord progression, and get capo fret picks favoring easy open keys.

Guitar String Tension Calculator

Set scale in inches or mm, pick E1-E5 notes, gauge and plain/wound, and read per-string tension via D Addario formula.

Gym Interval Timer

Loops a 5-second prep, WORK, and REST cycle with phase color shifts, last-3-second beeps, and Wake Lock for the screen.

Haiku & Tanka Rhythm Checker

Real-time mora counting for Japanese haiku (5-7-5) and tanka (5-7-5-7-7). Exports vertical tanzaku-style PNG.

Hamming Distance Calculator

Count positions where two equal-length strings differ in binary, hex, or text, expanding hex to 4 bits and highlighting each differing position in red.

Handmade Price Tag Maker

Lay out brand-name price tags on A4 in rectangle, rounded, or circle shapes — up to 40 per sheet, exports 2x PNG.

Room Heat Loss & Heater Capacity Calculator

Estimate heat loss, heater output, and total seasonal cost (3–7 mo by region) from room size, insulation, and region.

Heat Press Settings Finder

Pick PU, glitter, stretch or sublimation vinyl with cotton, polyester, blend or nylon for temperature, time, pressure.

Hidden Character Revealer

Detects 24 invisible/control chars (ZWSP, BOM, RTL marks, NUL) with U+XXXX badges and outputs a cleaned copy.

Hiking Trail Food Calorie Calculator

Computes burn from body, pack, and ascent/descent hours via METs and shows trail-food weight at 5 and 4 kcal/g.

HKDF Key Derivation Calculator

Enter IKM, salt and info, then pick SHA-256/384/512: RFC 5869 Extract returns PRK and Expand returns OKM at the chosen byte length, all in hex.

Hole Saw RPM Calculator

Computes ideal RPM from diameter and material (wood 60, alu 45, steel 30, inox 15 m/min) with a 4-step trigger guide.

Homograph URL Checker

Scans URLs character by character against 50 Cyrillic/Greek look-alikes and 9 ZW/RTL controls with Looks-like map.

HOTP (RFC 4226) Counter Validator

Validate RFC 4226 HOTP codes against a ±N counter window. Generates 6, 7 or 8-digit HMAC-SHA-1 codes from a Base32 secret and flags counter resync drift.

HSTS Policy Builder & Validator

Generate a ready-to-paste Strict-Transport-Security header and validate it against five Chromium preload-list rules from your max-age and directives.

htaccess IP Restriction Builder

Builds Apache 2.4 Require ip and 2.2 Order Deny,Allow snippets from your allow-list and folder, with 403 recovery steps.

HTML Entity Encoder

Convert &, <, >, ", ' to &/</>/"/' entities. Escape and unescape in one bidirectional view.

HTML Table to Markdown Converter

Convert pasted HTML tables to GFM Markdown in your browser. Reads thead for headers and maps align attributes into left, center, or right separators.

HTML to JSX Converter

Convert HTML into React JSX by rewriting class to className, onclick to onClick, inline style strings to objects and self-closing tags, all in one pass.

.htpasswd Generator

Generate .htpasswd entries for Basic Auth with bcrypt, MD5 or SHA-1. Bulk user:pass mode included.

HTTP Cache-Control Header Builder

Compose a Cache-Control header from cacheability, max-age and revalidation flags, with built-in diagnostics for contradictory directive combinations.

HTTP Content-Disposition Header Builder

Build a Content-Disposition header per RFC 6266/5987. Pairs the ASCII filename with a UTF-8 filename* and flags non-ASCII or quote characters.

HTTP Cookie Prefix Validator

Paste Set-Cookie headers one per line to verify __Host- (Secure, Path=/, no Domain) and __Secure- (Secure) prefix rules with a per-line PASS/FAIL verdict.

HTTP Link Header (RFC 8288) Parser

Paste an HTTP Link header (RFC 8288) and break each link-value into its URI, rel tokens, and parameters. A quote-safe split keeps commas in quotes intact.

HTTP Status Code Dictionary

Browse 19 codes from 200 to 504 as searchable cards, filter by 2xx-5xx class, and toggle Animal Mode for http.cat.

HTTP Status Code Reference

Searchable reference of HTTP status codes with category filter and related headers.

HVAC Duct Velocity Calculator

Compute duct velocity and dynamic pressure Pv=1/2 rho V^2 from CFM and inch sizing, with ASHRAE 5-tier use diagnosis.

Daily Hydration Calculator

Estimate daily water from weight, exercise minutes, and climate, then split it into cups, bottles, and time slots.

Hydrometer Temperature Correction Calculator

Correct a hydrometer reading for the gap between sample and calibration temperature, showing adjusted gravity and change for values from 0.990 to 1.170.

IBU Bitterness Calculator

Estimate homebrew IBU and bitterness balance with the Tinseth formula. Get hop utilization, a 5-band scale and the BU:GU ratio for any batch.

Icon Grid Template Maker

Set columns, rows, cell size, padding, and gutter in pixels, then export a transparent PNG grid template with alignment guides for icon sets

ID Card Privacy Masker

Drag rectangular masks over ID card images, pick any mask color, then export a 2x resolution PNG via Canvas 2D.

L-Size ID Photo Tile Layout Maker

Tiles 30x40, 35x45, 24x30 and 40x50mm presets onto an 89x127mm L sheet at 300dpi (1051x1500 JPEG) with 1px cut lines.

Image Histogram Analyzer

Plot RGB and BT.601 luminance histograms with mean, min, max and clipping ratios; gamma slider highlights 0/255 in red.

Japan's Statutory Inheritance & Reserved Portion Calculator

Calculate Japanese statutory inheritance shares & reserved portions (Civil Code Art. 900/1042) by family structure.

Instagram Grid Image Splitter

Image splitter for Instagram grid posts: auto center-crop into 3x1, 3x2 or 3x3 tiles, download as 1080x1080 JPEGs.

Instagram Grid Preview

Arrange up to 9 photos in a 3x3 grid to see how your Instagram profile feed will look before you post. Drag to reorder and download the grid as a PNG.

Instagram Story Poll Safe Zone

Overlay top 250 px and bottom 340 px UI bands, a 50 px safe area, and poll, quiz, slider stamps on a 1080x1920 export.

Instagram Testimonial Maker

Build a 360x640 px PNG testimonial from review text, name and 1-5 stars across 3 templates and 4 color presets.

Instant Photo Print Composer

Drop a photo into Mini, Square or Wide polaroid frames with cover or contain fit, exported as a 2x rounded PNG.

Investment Simulator

Simulate compound growth from initial principal, monthly contribution, annual rate and 1-50 year horizon, with chart.

IP Address Type Classifier

Paste an IPv4 or IPv6 address to see its class, type, scope, and reserved range. Add a CIDR prefix to also get the network address and usable host count.

IP Subnet Calculator

Compute network, broadcast, host range, IP class, and 8-bit binary breakdown live from any IPv4 address and CIDR slider.

IPv6 Address Zero Compression Formatter

Enter an IPv6 address to see its RFC 5952 compressed form, full expansion, uppercase variant, and IPv4-mapped dotted form, plus zero-run and length stats.

ISO 8601 Duration Parser

Parse ISO 8601 durations (PnYnMnDTnHnMnS or PnW) into total seconds, milliseconds, minutes and hours, with a component breakdown and human-readable form.

ISO Week Number Calculator

Convert any date to its ISO 8601 week (1-53) and weekday (Mon=1), or reverse from year+week to Monday-Sunday dates. Matches Excel ISOWEEKNUM exactly.

IT Asset Tag Generator

Render up to 24 sequential asset tags on an 800px canvas with three corporate themes and 2x retina PNG export.

Ita-bag Badge Layout Simulator

Drag pin badges, heart buttons, acrylic charms and trading cards onto a true-scale ita-bag canvas. Color-code by oshi, drop in your own images, auto-fill to count how many badges you need, then export as PNG.

Japanese Era Converter

Convert Japanese eras (Reiwa, Heisei, Showa) to Western years. Calculates full age, traditional age, and school history.

Jaro-Winkler Similarity Calculator

Score two strings with Jaro and Jaro-Winkler similarity, broken into matches, transpositions, common prefix and window for name matching and dedup.

Jewelry Display Card Maker

Tile rectangular or circular cards across A4 with brand name, logo, 3 templates and an optional earring-hole guide.

Jewelry Casting Weight Converter

Convert master weight to required ingot mass via 9 presets from wax to pure gold and a 0-100% sprue margin slider.

JSON Diff Viewer

Paste two JSON objects into side-by-side panes; jsondiffpatch shows additions, deletions and changes as a color tree.

JSON Formatter & Minifier

Parse with JSON.parse, then re-stringify with 4-space indent or zero whitespace. Parser errors appear inline by cause.

JSON Key Path Navigator

Expand JSON into a tree and click any key or value to copy a path like store.book[0].price; hyphen keys auto-escape.

JSON Merge Patch (RFC 7396) Evaluator

Merge a patch into a target JSON by RFC 7396 rules (null deletes, scalars replace, objects recurse) and trace each set, remove and root step.

JSON Patch (RFC 6902) Evaluator

Apply an RFC 6902 JSON Patch in the browser: the 6 ops run in order, returning the patched JSON plus a per-op trace and the failing op[i] with its cause.

JSONPath Query Tester

Run JSONPath expressions on any JSON and see matched values, with root $, dot notation, brackets, wildcard, recursive descent, filters, and array slices

JSON Pointer (RFC 6901) Evaluator

Evaluate an RFC 6901 JSON Pointer like /users/0/name, decode ~0 and ~1 escapes, and trace each token with the resolved value or the exact failure reason.

JSON Schema Validator

Validate a JSON instance against a Schema in draft-07, 2019-09, or 2020-12 and see each error broken out by JSON Pointer path, keyword, and message.

JSON to CSV Converter

Convert JSON to CSV, TSV or semicolon, flatten nested keys with dot notation and union all keys to align sparse rows.

JSON to TypeScript Converter

Paste any JSON and infer key and value types into TypeScript interface or type definitions, with nested objects, arrays, and readonly modifiers.

JWT Generator & Debugger

Sign any payload with a secret via the Web Crypto API and generate HS256/384/512 JWTs live with 150ms debounce.

JWT HS256 Signature Verifier

Verify a JWT signature by recomputing HS256 from your secret. HMAC-SHA-256 over header.payload, base64url-compared in 3 states — RS256/ES256 not handled.

JWT Payload Viewer

Paste a JWT and split header.payload.signature into pretty JSON, with exp, iat and nbf decoded into readable local time.

Kanji Grade Level Checker

Classify text kanji against the MEXT 1026-char kyoiku-kanji table for grades 1-6 and flag out-of-grade kanji as badges.

Kaomoji Picker

Browse 255+ Japanese kaomoji across 6 mood tabs, search by bilingual tags, click to copy, last 20 kept in history.

Keyboard Event Viewer

Press any key to inspect key, code, keyCode, location and modifiers live. 50-event history plus preventDefault toggle.

Keyboard Cleaner

Lock keyboard for cleaning to disable keys while you wipe. Ripple effects, cat-mode alert, dual-path unlock.

Keyboard Ghosting & NKRO Test

Live keyboard tester for ghosting and NKRO. ANSI/JIS layouts, simultaneous key count and challenge mode.

Kindle Cover Mockup

Build a Kindle ebook cover with title, subtitle, author name plus three backgrounds (solid, gradient, angled stripes) — 1600x2560 PNG, Amazon KDP 1.6:1.

Kinetic Typography Generator

Split headlines into per-character spans, apply Bounce, Shake, Fade, or Glitch, and copy ready-to-paste HTML and CSS code for your project.

Knitting Decrease & Increase Row Calculator

Splits stitch changes evenly into two row-interval patterns and returns the exact shaping plan and total for sleeves and necklines.

Knitting Gauge & Pattern Resizer

Gauge (sts × rows per 10 cm) + size-mode (cm → counts) or pattern-mode (original → adjusted) → required cast-on counts.

Label Print Offset Calculator

Convert observed shift direction and amount (0-20mm, 0.5 step) into top/bottom/left/right margin offsets, export PNG.

Laminate Flooring Expansion Gap Calculator

Calculate the wall-side expansion gap for laminate, engineered, or solid floors. Combines 8mm safety base with thermal expansion to prevent buckling.

Late Payment Interest Calculator

Calculate late payment interest from principal, due date, payment date and annual rate. JP statutory rates supported.

Auto-Dispenser Detergent mL Calculator

Convert label water/detergent ratios to the per-30L mL value washer auto-dispensers expect, with concentrate correction.

LED Resistor Calculator

Find the series resistor for an LED from supply voltage, forward voltage and current, with the nearest E24 value, power dissipation and 4-band color code.

Letter Pack Plus Box-Fold Calculator

Computes 340×248mm Letter Pack Plus box-fold lines (H/2mm) and inner dimensions, with red dashed diagram and PNG export.

Levenshtein Distance Calculator

Computes the Levenshtein edit distance between two strings, with insert, delete, and substitute counts plus similarity percent and a normalized value.

NDC-Style Library Spine Label Generator

Generates a 3-row 220×300px library spine label using Japan NDC layout (class/book/volume), retina x2 PNG export.

Link-in-Bio Button Visual Designer

Live-previews link-in-bio button colors and radius on a 375×667 mockup, exports CSS snippets and a 750×1334 retina PNG.

List Randomizer

Shuffle and randomize a list with Fisher-Yates fairness. Optional dedupe, numbering, and split into N balanced groups.

Loan Repayment Simulator (Equal Payment / Equal Principal)

Loan & mortgage calculator: monthly payment, total interest, amortization, prepayment savings + term slider.

Loan and Mortgage Repayment Simulator

Compute monthly payment, total interest and yearly/monthly amortization for fixed loans with bonus prepayments built in.

Log-Normal Distribution Probability Calculator

Read the PDF, CDF and four moments of a log-normal distribution for any μ, σ and x, with the parameters and real mean, median and mode shown together.

Truth Table Generator

Type a logical expression with AND/OR/NOT/XOR up to 8 variables and the full truth table renders, ready to copy as TSV.

Long Sentence Highlighter

Split text by punctuation and flag each sentence in real time. Red marks length overflow, pink marks comma overuse.

Lorem Ipsum Generator

Pick paragraphs, words, sentences, or list items, set the count, toggle the Lorem prefix, and wrap output in HTML tags.

Luhn Checksum Calculator

Two-mode Luhn (Mod 10) tool: VERIFY validates a credit card or IMEI; GENERATE outputs the missing check digit with per-digit doubling and digit-sum trace.

Lumber Board Feet Calculator

Calculate board feet (BF) and volume from thickness, width, and length. Optional price per BF gives the total cost.

Macrame Cord Length Calculator

Find the exact cut length for each macrame cord before you start. Covers square, half hitch and spiral knots, with total cord by knot type and count.

Manga Manuscript Pixel Calculator

Pick a Japanese doujinshi finished size, 300/350/600dpi and bleed; outputs canvas pixels and a PNG with trim guides.

Manuscript Progress Visualizer

Fills a 20x20 genkoyoshi grid (400 chars/page) cell by cell as you type, with page tracker and 800x560 PNG export.

Manuscript to Book Pages

Text to book page converter: turn character count into paperback or hardcover pages, with density slider and cover PNG.

Markdown Link Extractor

Pull every link out of Markdown with its anchor text, URL, and line number in one list. Separates inline links from image syntax line by line.

Markdown Previewer

Type Markdown on the left and see GitHub-style HTML on the right with syntax highlighting, word count, and HTML copy.

Markdown Table to CSV Converter

Convert Markdown pipe tables into CSV or TSV with RFC 4180 auto-quoting for cells containing commas, quotes, or newlines, plus row and column counts.

Markdown to Plain Text Converter

Strip Markdown headings, bold, links, images, code blocks and tables into clean plain text. Links keep their label and images keep their alt text.

Markdown TOC Generator

Turn your Markdown headings into a paste-ready table of contents. Set H2-H6 depth, bullets or numbering, and GitHub anchors; fenced code # is skipped.

Mash Efficiency Calculator

Check your all-grain mash efficiency against the 65-80% range, with gravity points worked out from measured SG, grain weight and PPG potential.

Medal Rank Badge PNG Maker

Build a 1000x1200 PNG medal rank badge for Gold, Silver, or Bronze with ribbon, radial-gradient 3D finish, and toggleable light or dark background.

Medication Refill Sync Calculator

Enter each medication's stock and daily dose to compute run-out dates, then surface the earliest one as your next visit.

Global Meeting Planner

Worldwide meeting time planner: stack city timelines, auto-highlight overlapping business hours, click to set the slot.

Mel Scale ⇄ Hz Converter

Convert between Hz and the mel scale both ways using the O'Shaughnessy 1987 formula 2595·log10(1 + Hz/700), with 8 reference anchors from 20 Hz to 20 kHz.

Meta Tag and OGP Analyzer

Submit a URL to pull OGP, Twitter Card and JSON-LD tags, render a social preview card and run four pre-publish checks.

HTML Meta Tag Generator (OGP / Twitter Card)

Enter title, description, URL, OGP image, site name and Twitter handle to generate HTML meta tags for the head.

Metronome

BPM 40 to 250, time signatures 2/3/4/5/4 and 6/8, quarter to 16th plus triplet, three-tier accents.

Visual Metronome

Set BPM 30 to 280 with 2, 3, 4, or 6 beats and read tempo from screen flashes, beat dots, and a progress bar.

Mic Distance Inverse-Square dB Calculator

Applies 20·log10(d1/d2) to show the dB change and the gain offset needed to keep loudness constant at the new distance.

Microwave Wattage Time Converter

Enter the recipe wattage and time and your microwave's wattage; cook time is recalculated by fixed-energy physics.

MIDI Note Number Converter

Map any MIDI note number to its note name and frequency, and back again. Covers 0-127 and C-1 to G9, with the A4 reference adjustable from 380 to 500 Hz.

Midjourney Parameter & Shortcode Builder

Build Midjourney parameter strings (--ar, --stylize, --chaos, --sref/--cref) with sliders and dropdowns, ready to copy.

MIME Magic Byte Detector

Identifies 40+ file formats from the first 64 bytes (PNG, JPEG, PDF, ZIP, MP4), flags ZIP containers (docx, xlsx, jar), and warns when the extension lies.

Monitor Dead Pixel Checker

Flood your screen with solid red, green, blue, white and black so dead pixels and always-on stuck pixels stand out, cycling all 5 colors full screen.

Morse Code Translator

Convert text to international or Japanese Wabun Morse code in real time, with adjustable WPM, tone and visual lamp.

Multi-Event Probability Calculator

Enter 2-10 independent event probabilities to compute all-occur, at-least-one, none, exactly-one, and expected count together in one view.

Nail Tip Size Matcher

Enter your nail width in mm and pick oval, very-short, or square to see the closest tip number plus the adjacent ones.

ND Filter Shutter Speed Calculator

Pick a base shutter from 56 stops and an ND density from ND8 to ND100000 to get the new SS in s, min or h.

Negative Binomial Distribution Probability Calculator

Read PMF, CDF, and survival of the negative binomial NB(r, p) plus mean, variance, and mode at once. Covers r 1-1000, p 0.01-0.99 with log-gamma precision.

Negative Split Pace Calculator

Plan a negative split race: enter target time, get first-half and second-half paces plus a 5 km/mi split table for full or half marathon.

Notion Cover Builder

Build 1500x600 Notion cover PNGs with solid, gradient, grid, or dots backgrounds, 3 text alignments, and a 1170x230 safe area for mobile.

Novel Dialogue Ratio Checker

Counts text inside Japanese 「」『』 quotes to score your dialogue-to-narrative ratio across three pacing tiers and exports an 800x450 share PNG.

Novel ruby density analyzer

Normalizes Aozora |kanji《ruby》, post-kanji《ruby》 and (kana) notations to show kanji and ruby rates as SVG charts.

Odds Probability Converter

Converts implied probability, decimal, fractional, and American odds in any direction, with the payout and profit on a 100-unit stake.

OG Image Simulator

Drop an OG image to preview X, Facebook, LinkedIn and Discord cards side by side, with safe-area and circle-crop guides.

1RM Calculator

Estimate one-rep max via Epley, Brzycki and Average formulas, with a 50-100% intensity table linked to a barbell layout.

One-sheet A4 zine maker

Imposes 8 pages onto a single A4 with rotated top row, exporting a 1752x1240 PNG with cut and fold guides.

Oshi color palette card maker

Pick three Main/Sub/Accent colors and an oshi name to render a 640x360 card in stripe, block or gradient style.

Ovulation Calculator

Set last period, cycle and luteal phase (10-16 days) to map ovulation and the 6-day fertile window over two cycles.

Page number asset generator

Pick A5/B5/A4 at 350dpi and rtl or ltr binding to export transparent PNGs for every page with five decoration formats.

Paint Mixing Ratio Calculator

Calculate each component’s volume and whether there is enough paint from the total volume, mix ratio, area, and coats.

Image Palette Extractor

Resize an image to 100 px on Canvas, quantize RGB to 5 levels, and surface the top 8 colors as HEX, RGB, and HSL cards.

Parking Lot Map Maker

Draw a shop parking diagram with 3 to 15 spaces, highlight your reserved spots, and export as PNG.

Passport Photo Cropper

Crop photos to JP 35×45mm, US 2×2in or EU 35×45mm specs with head and chin guideline overlay, then export a 300 DPI PNG.

Password Generator

Generate 8 to 64 character cryptographic passwords with Web Crypto API and a four-step strength bar.

Password Shannon Entropy Calculator

Measure password length, charset pool, brute-force bits and Shannon entropy, then estimate crack time under online, offline-KDF and GPU attacker models.

Password Strength Checker

Score your password 0–4 with zxcvbn, see realistic offline crack time, warnings and improvement tips, all in browser.

Password Strength Meter & Improvement Suggestions

Entropy bits + online/offline/GPU crack-time + 7-criteria checklist (length, case, digits, specials, common, pattern).

Percentage Calculator

Compute percent of total, ratio, and percent change live, visualized with bar, donut, and before/after charts.

Percentage Change Calculator

Four tabs: basic ratio, before-to-after change, value with ±p%, and reverse from discounted price.

Permissions-Policy Header Generator

Toggle 8 web features with none/self/all/custom origin and emit headers for Raw, Nginx, Apache, and Node.js.

Perspective Grid Generator

Generate 1-, 2-, or 3-point perspective grids in 16:9, 4:3, 1:1, or A4 presets with custom line color and export the result as PNG for drawing references.

PFC Balance / Macro Calculator

Set your daily kcal goal and P/F/C ratio sliders for exact protein, fat, carb grams. Balanced, Muscle and Keto presets.

Phone Wallpaper Lock Screen Preview

Drop the iOS or Android lock screen clock and home bar over your wallpaper, drag to fit and export with or without UI.

Photo Aspect Ratio Cropper

Crop photos to 16:9, 4:3, 1:1, 9:16 or a custom ratio with a draggable overlay, then download as PNG. Images stay in your browser.

Picture Frame Mat Calculator

Enter your frame opening and artwork size to get exact top, bottom, left and right mat borders plus the window cutout, in even or bottom-weighted layout.

Pipe Flow Velocity & Reynolds Number Calculator

Compute flow velocity, Reynolds number, flow regime, and pressure drop from pipe inner diameter and flow rate.

Varispeed Calculator

Pitch and BPM sync calculator: convert tempo changes to semitones, or pitch shifts to a new BPM, in real time.

Sprite Sheet Frame Timing Calculator

Calculate ms per frame and FPS for sprite animations instantly — 60/30/120 base FPS presets, per-frame or target-FPS modes with live flip-book preview.

Pixel Art Editor

Draw on 16/32/64 grid with pen, eraser and flood fill, manage frame timeline and export PNG or horizontal sprite sheet.

Pixel Art Grid Maker

Draw pixel art on an 8x8 to 64x64 grid by clicking or dragging, pick from a 12-color palette plus your own colors, and export a transparent PNG.

PKCE Code Verifier Generator

Generates a PKCE code_verifier with its S256 code_challenge per RFC 7636 — pick 43-128 chars and copy ready-to-paste /authorize and /token request snippets.

Plant Care Label Maker

Compute the next watering date from a 1 to 90 day cycle and export a 360x240 retina PNG in three label styles.

Plus Codes Converter

Convert Plus Codes (Open Location Code) to lat/lng and back at 10, 11, or 12-digit precision. Shows SW/NE corners and the cell size in metres.

Podcast Cover Art Builder

Build 3000x3000 square podcast covers for Spotify / Apple Podcasts with 4 palettes (Sunset, Ocean, Forest, Mono) and 3 background patterns.

Poisson Distribution Probability Calculator

Get the Poisson PMF, CDF and survival in one view, with mean, variance, mode and standard deviation. Log-gamma engine stays stable to λ=1000, k=2000.

Polaroid Photo Frame Export

Wrap a photo in a polaroid-style 1200×1500 PNG with caption and date / place note. White / Kraft / Dark frame, -5° / 0° / +5° tilt, drop shadow included.

Pomodoro Timer

Three 25/5/15-minute presets with auto phase switching, SVG ring progress, tab-title countdown and Web Audio chime.

Pomodoro Focus Tracker

Logs task names and end times to localStorage. 25/5 cycles auto-extend to a 15-min long break every 4 sessions.

Pool Volume Calculator

Calculate pool water volume in liters, US gallons, and cubic meters across 4 shapes. Handles sloped-floor average depth and shows an estimated fill time.

Port Number Dictionary

Bidirectional lookup of 24 well-known ports by number or service, with a per-row 1.5-second no-cors localhost probe.

Poster Font Size Calculator

Find legible poster font sizes from viewing distance and sheet format. Covers A0-B4 and custom mm sizes, with title, subtitle and body pt plus preview.

Potting Soil Volume Calculator

Get required liters of potting soil and how many 5L/14L/25L bags to buy from pot shape, size, and quantity.

PPI Calculator

Calculate PPI and dot pitch from resolution and inches, with sharpness rank and side-by-side history of monitors.

Presentation Script Summarizer

Extracts the top 8 frequency keywords from a pasted script, scores sentences and surfaces the three highest with marks.

Pricing Table Card PNG Maker

Build a 1200x800 PNG pricing-table card with 3 tier columns, plan name and price inputs, a per-column features list, and a MOST POPULAR highlight badge.

Prime Number Checker

Test primality up to 16 digits, see prime factorization, find nearest primes, and list primes up to 100,000.

Priming Sugar Calculator

Work out the corn sugar or table sugar needed to bottle-condition beer from batch volume, temperature, and a target of 1.5-4.0 CO2 volumes.

Hairline & Tiny Text Print Checker

Check if 0.25pt hairlines and small text survive offset printing — instant SAFE/WARN/NG verdict, DPI-aware pt/mm conversion, downloadable PNG report.

Printable Shipping Gauge

Generates an A4 or postcard ruler with 1/2.5/3 cm cutout slits via Canvas at 96 DPI true scale, exported as PDF or PNG.

Product Description Generator

Pick a tone (professional/sales/story/minimal) and get two description drafts plus ten SEO hashtags.

Product Size Visualizer

Enter width and height in mm to render an 800x800 PNG with coin, IC card and phone references.

Hiraku Kanji Checker for Web Writing

Detects 64 standard hiraku-kanji pairs (出来る → できる, 頂く → いただく) by longest match in Japanese text, with hiragana copy.

Progress Tracker Image Card

Build a 1200x630 PNG progress card for any goal with rounded, square, or 20-segment bar styles. Renders as Open Graph share size across socials.

Proofreading Mark Generator

Render six JIS proofreading marks with custom text, red/blue/black ink and stroke, exported as 400x300 transparent PNG.

Propeller Pitch Speed Calculator

Estimate a boat's theoretical and real speed from propeller pitch in inches, engine RPM, and a 0-50% slip allowance, shown in mph, km/h, and knots.

Push Notification JSON Payload Builder (FCM / APNs)

Generate FCM (HTTP v1) and APNs push notification payloads side-by-side. Supports badge, sound, and custom data fields — copy-ready JSON, no upload.

QR Code Generator

Generate QR codes from URLs or text instantly with high error-correction (Level H). Download as image.

QR Code Error Correction Calculator

Data size + error level (L/M/Q/H) → min QR version, modules, remaining capacity, print size, with L/M/Q/H comparison.

QR Code Print Size Calculator

Sizes modules from 0.25mm and totals from 15mm via scan distance, URL length and ECC, with a dimensioned PNG spec sheet.

Quaternion Rotation Multiply Calculator

Multiply two quaternions (w,x,y,z) with the Hamilton product to compose 3D rotations, then read the result quaternion, norm, and rotation axis-angle.

Raised Bed Soil Calculator

Enter your raised bed's length, width and fill depth to get the soil volume in liters and cubic meters, plus how many bags you need, rounded up.

Random Number Picker

Pick numbers in a range with crypto.getRandomValues and rejection sampling — no modulo bias, no Math.random.

Reaction Time Test

Click the red-to-green transition for 5 trials. Average ms is shown with a 5-tier reflex rank from fastest to slowest.

English & Japanese Readability Scorer

Scores English with Flesch Reading Ease, Flesch-Kincaid Grade and Gunning Fog, and Japanese by average sentence length.

Printable Recipe Card PNG Maker

Build A5 portrait 1748x2480 (300dpi) printable recipe card PNGs with title, servings, time, up to 12 ingredients and 12 steps in Cream, Mint, or Slate.

Reciprocity Failure Calculator

Enter your metered seconds and a film's reciprocity exponent p to get the corrected shutter time and extra stops for long exposures. Under 1 s, no change.

Regex Character Class Builder

Toggle 8 categories (digits, letters, spaces) plus custom characters to build a JS regex class [...] or [^...] and highlight matches in a test string.

Regex Tester with Token Breakdown

Run a JavaScript regex with g/i/m flags on a test string, highlight matches and break the pattern into 16 token notes.

Regex Tester & Visualizer

Highlight matches for a regex pattern, with capture group inspection and ready-to-paste code for JS / Python / Go.

Resale Bottom Price Calculator

Back-solve the minimum sale price from fee rate, shipping, packaging and target profit with a full breakdown.

Resale Item Numbering Badge

Generate up to 100 round numbered badges from a start-end range and download each as a transparent PNG.

Resin Weight Calculator

Get exact resin grams and milliliters from mold shape (cuboid, cylinder, sphere, hemisphere), size and specific gravity.

Resume Keyword Extractor

Paste resume and JD to extract keywords, compare matched, resume-only, and JD-only sets, and see your ATS match rate.

Reverse Text Generator

Flip any text into reversed order in real time. Surrogate-pair safe — emoji and rare CJK reverse cleanly per code point.

Rhythm Game Hi-Speed Calculator

Compute the optimal Hi-Speed multiplier from BPM and target green-number, with a 0.25-step HS candidate table.

Japanese Rice Cup (Gou) to Grams Converter

Convert Japanese rice cups (gou) ↔ grams ↔ ml. 1 gou = 150g/180ml raw, with water and cooked weight.

Rice-to-Water Ratio Calculator

Calculate the optimal amount of water from the number of cups, rice variety, desired texture, and cooker type.

Ring Size Converter

Convert JP ring number, inner diameter, and circumference, with simultaneous US/UK/EU mapping and on-screen ruler.

robots.txt Generator

Build robots.txt from per-user-agent Allow/Disallow rules, with sitemap line, crawl-delay, and one-click presets for blocking AI bots or a standard setup.

Roman Numeral Converter

Convert Roman numerals 1-3,999 both ways instantly, with additive/subtractive breakdown (IX = 10-1) and a built-in practice quiz — free, no signup.

ROT13 and Caesar Cipher

Slide the shift from 1 to 25 with a live A to Z mapping row. Encode spoilers, decode rot ciphers, study Caesar.

ROT47 Cipher Encoder / Decoder

Apply ROT47 to printable ASCII 33-126, shifting each by 47 to scramble digits and symbols, not just letters. Two passes restore the original.

Rowing Split Calculator

Convert between your /500m split time and watts both ways with the Concept2 formula, with watts, pace and an estimated calories-per-hour figure.

Running Pace Calculator

Enter any two of distance, time, and pace to solve for the third. Includes 5K/10K/half/full presets, a per-mile/km split table, and a min/mile toggle.

Sail Area to Displacement Ratio Calculator

Work out a sailboat's sail area to displacement ratio from its sail area and weight, and see whether it reads as heavy/cruising, moderate, or performance.

Save the Date Card PNG Maker

Build 5x7 landscape 1500x1050 PNG save-the-date cards with couple names, date, location, and Floral, Coastal, or Minimal themes plus corner leaf ornaments.

Scientific Notation Converter

Two-way convert decimals and E notation (e.g. 2.5e-4, 1.5e-3) in real time, with a 1-15 sig-fig slider.

Screen Info and Breakpoint Inspector

Live view of viewport, screen, DPR, color depth, orientation and Tailwind breakpoints with searchable property dump.

Script Line Highlighter

Paste a role and script: lines starting with the role highlight fully, mid-line mentions only the name. PNG export.

Search Ad Copy Previewer

Check 3 headlines (30 bytes) and 2 descriptions (90 bytes) with halfwidth=1/fullwidth=2 byte rules and SERP preview.

CSP Header Generator

Pick from 11 presets (GA, YouTube, Maps, jsDelivr) and emit CSP headers as Apache, Nginx or HTML meta tag.

SemVer Range Checker

Test whether a version matches a range, with carets, tildes, x-ranges, comparators and hyphen ranges parsed into the minimum and maximum versions allowed.

SemVer Version Comparator

Parse two version strings per SemVer 2.0.0 into major, minor, patch and pre-release, then return a strict A < B / A = B / A > B precedence verdict.

Google SERP Pixel Width Previewer

Measures title (600px) and meta (960px PC / 680px mobile) widths via canvas measureText and exports a 652px SERP PNG.

Sewing Pleat Calculator

Solve pleat depth and total fabric width both ways from waist and pleat count, with marking intervals.

Shelf Sag Calculator

Enter shelf span, depth, thickness, load and 5 wood types; sag is calculated with safe/caution/danger rating and SVG.

100-yen Shop Box Matcher

Enter W/D/H of your item and match against 5 Japanese 100-yen-shop boxes (Nekoposu, Yu-Packet) with rotation fit.

Shipping Volumetric Weight Calculator

Compute volumetric and chargeable weight in metric (cm/kg ÷5000/6000) or imperial (in/lb ÷139/166).

Shoe Lace Length Calculator

Pick cross or parallel lacing, 2-12 eyelets and 2.0-8.0 cm spacing, get a length with 45 cm bow plus a stock cm size.

Shoe Size & Width Converter

Convert foot length and girth into JIS / US / EU / UK shoe sizes and the JIS width rating (A to G).

Shugibukuro Envelope Template

Render Japanese shugibukuro envelope titles and names vertically in Noto Serif JP and export 105×185 or 125×205 mm PNG.

Shutter Angle to Shutter Speed Calculator

Get the exact shutter speed in seconds for any frame rate and angle — 1/48s at 24fps, 180°. Shows fraction, milliseconds, and decimal seconds.

Sidechain Release Time Calculator

Get the beat-synced compressor release in ms from any BPM and note value, with straight, dotted and triplet figures for sidechain pump.

Signage Letter Size Calculator

Signage calculator: enter distance, audience (pedestrian/elderly/driving) and board size to get min letter size and fit.

Simple Syrup Ratio Calculator

For a 1:1 batch finishing at 500ml, work back to about 307g sugar and 307ml water. Pick 1:1, 2:1, or a custom by-weight ratio, displacement included.

Sleep Cycle Calculator

Find ideal wake or bedtimes with the 90-minute sleep cycle. Shows 1-6 cycle options with countdown timers per slot.

Sleep Debt Calculator

Log up to 30 nights of sleep against your target to see total sleep debt in hours, a 2-night or 7-night recovery plan, and a four-level severity tag.

URL Slug Generator

Split titles via Intl.Segmenter and convert hiragana/katakana to romaji with kanaMap to produce kebab-case URL slugs.

Weekly Business Hours Card Maker

Build 360x640 weekly business hours cards as PNG with three neon themes via Canvas 2D.

Product VS Comparison Matrix Maker

Render A/B product specs and verdict into 1080x1080 or 1080x1350 VS comparison PNG cards.

Profile Picture Safe Area Preview

Preview your profile picture's circle crop and safe area instantly. Matches Instagram, X, LinkedIn, and TikTok avatars — PNG export, no upload.

SNS Video Safety Zone Simulator

Preview where TikTok, Reels, and Shorts UI cover your 9:16 video before posting. Browser-only.

Social Media Bio Generator

Plug keywords into 4 tones (professional, casual, creative, minimal); auto-trim for X 280 or Instagram 150 chars.

Sock Knitting Stitch Calculator

Work out your sock cast-on from gauge and foot circumference. Heel, toe and gusset counts appear too, rounded to a multiple of 4 with adjustable ease.

Solar Panel Angle Calculator

Calculate the optimal solar panel tilt angle by latitude for each of 12 months and find the year-round best angle.

Sound Travel Distance Calculator

Calculate how far sound travels or how long it takes from the temperature-adjusted speed of sound, plus a flash-to-bang lightning-distance mode.

Sourdough Hydration Calculator

Get the added water for a 75% hydration target, with the starter split into its own flour and water. Current hydration and totals stay visible.

Sourdough Starter Feeding Calculator

Work out starter, flour and water in grams from either the starter you have or the total you want, with an adjustable feeding ratio and hydration.

Speaker Crossover Calculator

Compute capacitor μF and inductor mH for a 1st-order Butterworth (-6dB/oct) crossover from impedance and frequency.

Speaker Wire Gauge Loss Calculator

Toggle AWG 8-24 or mm² 0.2-10, set length 1-100m and 4/6/8/16 ohm to see loss and the minimum gauge under 0.42dB.

Speech Time Estimator

Speech time calculator: estimates reading time from word & character count with slow/normal/fast presets and timer.

Spring Compression Calculator

Spring rate, maximum force, deflection, solid height, and index for a helical compression spring, based on its wire, coil size, active coils, and material.

Sprite Sheet Coordinate Generator

Output per-frame (x, y, w, h) JSON and CSS background-position rules for uniform-grid sprite sheets, with padding and margin for extrude-aware exports.

SQL Formatter

Format SQL in 6 dialects (MySQL, PostgreSQL, T-SQL, SQLite, PL/SQL) with 300ms debounce, indent and case toggles.

SQL Formatter & Beautifier

Reformat cramped SQL into a clause-per-line layout with 4-space indentation, uppercase keywords, and color highlighting across 100+ reserved words.

SRI Hash Generator

Generate SHA-256/384/512 SRI hashes from JS/CSS code or files via crypto.subtle, with auto-built integrity tags by URL.

SSH Key Fingerprint Viewer

Paste an OpenSSH public key to view its SHA-256 and MD5 fingerprints, key type, bit length, and comment, all parsed locally in your browser.

SSH ProxyJump Config Block Builder

Generate two-block ssh_config with ProxyJump from bastion and target Host fields in real time.

Staircase Riser & Tread Calculator

Calculate stair riser height and tread depth with building code compliance check.

Postage Stamp Combination Finder

Knapsack DFS picks five Japan-Post stamp combos that match or minimally exceed your target sum.

Japan Stamp Duty Judge Calculator

Computes Japanese stamp-duty (Inshi-zei) for four doc codes and quantifies savings from net-amount split.

Steam Capsule Image Builder

Build a Steam Header Capsule with title, tagline, genre tag plus 3 backgrounds (solid, gradient, vignette) — 920x430 PNG, color + text-color pickers.

Stereo Tester

Play L/R, in-phase/out-of-phase, panning and 100Hz/1kHz/10kHz tones to verify headphone and speaker channels.

Sticker Sheet Layout Calculator

See how many stickers fit on one sheet from your sizes. A4/A5/Letter presets, rectangle/circle/rounded shapes, plus margin and spacing on a layout preview.

Stock Nanpin (Average-Down) Calculator

Enter current holdings (shares + avg price) and a new purchase to compute total shares, new average cost, and funds.

Stopwatch

Measures elapsed time at 1/100 second precision with stacked lap history; auto-switches to hh:mm:ss.cs past one hour.

Printable Storyboard Frame Sheet

Build an A4 portrait storyboard sheet at 300 dpi (2480×3508 PNG): pick 6 / 9 / 12 frames and 16:9 / 4:3 / 1:1 aspect, each cell numbered with 3 note lines.

Stream Thumbnail Maker

Compose YouTube and Twitch thumbnails with 5 layouts, 8 bubbles, 12 manga effects. Drag and export 1280×720 PNG.

Strike Water Temperature Calculator

Hit a 67°C mash with strike water heated to the exact degree. Built for all-grain mashing in with the Palmer formula — qt/lb and L/kg, plus total volume.

Studio Room Mode Calculator

Computes axial, tangential and oblique modes up to 250Hz from L/W/H with a canvas chart and tab-separated export.

Subnet Mask Cheat Sheet

Search the /0-/32 subnet cheat sheet, click to copy a mask, and calculate network, broadcast and hosts from any IP/CIDR.

Subwoofer Port Length Calculator

Compute bass-reflex port length from box volume, tuning frequency and diameter. Toggle end correction (k=0.825) for DIY.

Sunny 16 Calculator

Find the shutter speed for any aperture with the Sunny 16 rule. Pick 1 of 5 lighting conditions plus your ISO and f-stop to expose film without a meter.

SVG Optimizer

Paste SVG markup or upload a .svg, then strip comments, metadata, attributes and round decimals. Side-by-side preview.

SVG Path Coordinate Sampler

Convert an SVG d attribute into evenly sampled coordinate arrays as JSON. Visualize how curves decompose into points and pass coordinates to environments without SVG DOM API access (Arduino, plotters, Excel, embedded firmware) or use as input material for LLM-driven shape work.

SVG Placeholder Generator

Build SVG dummy images with width, height, colors and font 1-500 px; copy as base64 data URI for img src or save SVG.

SVG viewBox Cropper

Computes a tight bounding box via getBBox with rect/circle fallback, then rewrites viewBox and strips width/height.

SVG Wave Generator

Generate layered SVG wave dividers for web sections. Adjust height, frequency, 1-5 layers and a two-color gradient, then copy the code or download the SVG.

Swim Pace Calculator

Enter a swim distance and time to get pace per 100m, speed in km/h and m/s, plus even-pace split projections for 50m to 1500m races.

Syllable Counter

Count English syllables instantly. Silent-e and vowel-cluster rules for lyrics, poetry, haiku 5-7-5, and speeches.

Synth Envelope BPM Sync

Turns BPM and note length, with dotted or triplet modifiers, into release time in ms and plots the envelope curve.

systemd Timer / cron Converter

Two-way POSIX cron and systemd OnCalendar converter with a 5-fire preview, ready-to-paste .timer unit or crontab line, and non-roundtrip warnings.

T-Distribution Probability Calculator

Computes Student's t-distribution PDF, CDF, and p-value for any degree of freedom from 1 to 1000, with one or two tailed tests and significance grading.

Tangzhong Calculator

Get exact flour and water grams for an 8% tangzhong roux. Total flour splits into the cooked paste and main dough at a 1:5 ratio, sized for milk bread.

Tarot One Oracle

Draw one card from the 22 Major Arcana for a daily reading. Upright/reversed differs; export a downloadable image.

Regional Tatami Size Converter

Enter tatami count in 0.5 steps to compare four Japanese standards (Kyoma, Chukyoma, Edoma, Danchima) and m².

Tategaki SNS Card Maker

Renders Japanese vertical text to 1080 or 1920x1080 PNG with rotated dashes and repositioned kana punctuation.

Japan Income Tax Bracket & Marginal Rate Calculator

Apply Japan income tax across all 7 progressive brackets (5-45%), compare marginal vs effective rate, and toggle the 2.1% reconstruction surtax.

Japan Social Insurance Wall Calculator (1.06M / 1.30M JPY)

Monthly/hourly wage, company size, region → social insurance wall (1.06M/1.30M JPY) take-home drop + recovery target.

TCG Deck Balance Calculator

Uses the hypergeometric distribution to chart opening-hand probability and the count needed to clear 80% and 90% lines.

TCG Proxy Print Resizer

Place cards on a 350 DPI A4 canvas at exact 63×88mm Standard or 59×86mm Small with dashed cut guides, then export PNG.

TCP Bandwidth-Delay Product (BDP) Calculator

Size your TCP window from the bandwidth-delay product: enter link speed and RTT for BDP in bytes, KiB, MiB and packets, a 64 KiB cap and a scaling check.

TDEE & Macro Calculator

Mifflin-St Jeor BMR × 5 activity levels yields TDEE; maintain, cut (-500), or bulk (+300) macros in P/F/C grams.

Text Art Generator

Type any text, apply neon glow, 3D pop, sunset gradient, outline or retro 80s styles, and export the art as a PNG image.

BLEU Score (Bigram) Calculator

Computes the BLEU-2 score for a reference and candidate pair, blending 1-gram and 2-gram precision with a brevity penalty and zero-count smoothing.

Text Case Converter

Convert text across 10 case styles including camelCase, snake_case, kebab-case and CONSTANT_CASE, with a character and word count beside the input.

Text Case Randomizer

Convert English text in 4 modes: random, alternating (aLtErNaTiNg), inverse, and capitalize, with copy and share-to-X.

Text Character Frequency Counter

See how often each character appears in pasted text and its share. Toggle case, skip whitespace, sort by frequency or code point, view a chart.

Text Cleaner

Trim line edges, drop empty lines, collapse runs of whitespace, or strip all spaces with toggle flags.

TF-IDF Cosine Similarity Calculator

Enter two texts to compute smoothed TF-IDF (N=2) cosine similarity, with shared vocabulary, total terms, and each vector norm shown in one panel.

Text Diff Checker

Side-by-side line comparison with color-coded added, removed, and changed lines plus an ignore-whitespace toggle.

Word-Level Text Diff

Compare two texts word by word and highlight added, removed, and unchanged words in color, with a similarity percentage shown alongside the diff.

Text Encryption Tool

AES-encrypt text with a password in your browser. The share URL auto-opens decrypt mode for the receiver.

English Word Inflector

Paste a list of English words and switch them to plural, singular, or past tense at once with spelling rules.

Text Jaccard Similarity Calculator

See the Jaccard index and distance for two texts. Switch word, 2-gram, and 3-gram tokenization with case folding for plagiarism and duplicate checks.

KMP Pattern Search Step Counter

Build the KMP failure-function (LPS) table, list every match index, and compare the linear-time KMP comparison count with a naive search on the same text.

Text Line Sorter & Deduplicator

Sort text lines A-Z or Z-A, reverse or shuffle them, and strip duplicate or empty lines with 6 one-click actions. Built for cleaning up lists fast.

Text Repeater

Repeat any string up to 100,000 characters with space, newline or comma separators, then copy or download as .txt.

Text Repetition Finder

Paste text to surface repeated phrases and redundant wording, each color-coded. Tune phrase length and minimum count, then review matches by frequency.

Text Shortener

Shorten any text to 20%, 50% or 80% by extracting top-scoring sentences. Position bias keeps intro and conclusion.

Keyword Extractor and Sentence Summarizer

Intl.Segmenter word frequency surfaces top-10 keywords; sentences scored by density and log length yield the top ~30%.

Voice Dictation

Web Speech API transcribes the mic feed in real time, auto-inserts punctuation and appends to the textarea.

Text Tone Analyzer

Tone checker for email and social posts. Scores sentiment, formality and humor on a radar chart with tips.

Vertical Writing Converter

Preview Japanese text in vertical writing. 5 font families plus size and line spacing for fanzines and web design.

Frozen Meat & Fish Thawing Time Calculator

Combines weight, a thickness curve, beef/pork/chicken/fish coefficients and fridge, room or running-water methods.

Thesis Citation Cross-Checker

Paste your draft and bibliography to cross-match APA, IEEE, and MLA — a reference checker that flags missing entries.

Tile Quantity Calculator

Surface, tile size, joint, and 5-15% waste — rows x cols, count, recommended order, layout preview. US or metric.

Time Duration Calculator

Compute the duration between two times or sum multiple intervals, with overnight handling and decimal hour output.

Travel Tip Calculator

Pick 10, 15, or 20 percent service, set the bill and party size, and see tip, total, and per-person share.

Plus-Sizing Tire Pressure Converter

Enter OEM and new tire load index, standard and pressure to back-calculate the kPa needed to keep load capacity. STD/XL.

Online Tone Generator

Play sine, square, sawtooth and triangle waves on a 20Hz–20kHz log slider, with frequency sweep and L/R pan.

AI Transcript Timestamp Remover

Strip [00:12:30] timestamps, speaker labels, and VTT/SRT codes from Whisper, NotebookLM, or Otter transcripts.

TRPG Log Speaker Extractor

Pull one character lines out of TRPG chat logs; auto-detects separators and trailing timestamps line by line.

Twitch Panel Image Builder

Generate Twitch channel panel PNGs at 320×160 (2:1). Set title + subtitle, pick 4 icons (Play, Heart, Link, Dot) and 3 strips — under 1MB ready to upload.

Typing Speed Converter (WPM/CPM/KPM)

Convert WPM, CPM, and KPM in any direction with the 5-character word standard, Japanese romaji (6.7) and kana (3.5) keystroke models, and 6 skill tiers.

ULID Generator and Decoder

Generate a 26-char Crockford Base32 ULID, or paste one to decode its 48-bit millisecond timestamp, 80-bit random tail, ISO 8601 UTC date and validity.

UL Pack Base Weight Calculator

Tag each item as worn or consumable to split Base, Pack and Total weight live, then copy with the tags inline.

Unicode Codepoint Lookup

Convert characters and Unicode codepoints both ways, listing each codepoint with its UTF-8 and UTF-16 byte sequences, character name and block.

Unicode Escape Converter

Encode and decode between JS \uXXXX, CSS \XXXX and HTML &#xXXXX; with surrogate pair detection and multibyte-only mode.

Unicode Normalization Converter

Convert text into NFC, NFD, NFKC and NFKD side by side, with per-form character and UTF-8 byte counts plus byte deltas for normalization diagnosis.

Storage Unit Converter

Convert across TB, GB, MB, KB and Bytes on 1024 binary base with live two-way updates and a copy button on every field.

Unit Price Calculator

Compare price per ml, gram or unit across products with different sizes to instantly find the cheapest option.

Unix Timestamp Converter

Convert Unix seconds to date and back in UTC, local and datetime-local. Current Epoch ticks live every second.

URL Encoder Decoder

Apply encodeURIComponent or decodeURIComponent to the textarea; malformed percent escapes surface as an error.

URL Parser & Breakdown

Paste any URL to split it into 6 parts: protocol, host, port, path, query parameters and fragment, each color-coded in a copyable table for debugging.

URL Tracking Parameter Stripper

Strip UTM, gclid, fbclid and 15+ click IDs plus Amazon/X/YouTube/TikTok-specific params via regex.

User-Agent Analyzer

Parse your User-Agent into browser, OS, device, engine and CPU via ua-parser-js. Paste any UA to check spoofing.

UTF-8 Byte Counter

Counts UTF-8 bytes, code points, UTF-16 units, and lines side by side, with a 4-category byte breakdown (ASCII, Latin, CJK, emoji).

UUID v4 Generator

Generate up to 100 UUID v4 at once via crypto.randomUUID, with hyphen-strip option and copy button.

UUID Version Detector

Paste a UUID to detect its version (v1-v8, Nil, Max) and variant (RFC 4122 etc.), with the version nibble colour-coded and v1, v6, v7 timestamps decoded.

VAT and Sales Tax Calculator

Reverse net to gross or gross to net, choose floor, round, ceil or none, and stack multiple lines for invoice totals.

3D Vector Calculator

Enter two 3D vectors (x, y, z) to get magnitudes, unit vectors, dot and cross products, angle in degrees and |A×B| together, with 2-8 decimal precision.

Phone Vibration Tester

Test your phone's vibration motor in-browser with short, long, heartbeat, SOS presets plus a custom pattern recorder.

Subtitle CPS Calculator

Compute characters-per-second from text and seconds, with safe/warning/over verdict at JA 4.5-6 and EN 15-20 cps.

Visual Countdown

Set minutes and seconds; a circular SVG gauge shifts color at 50% and 15% remaining, then beeps 880 Hz at the end.

Wallpaper Repeat & Roll Calculator

Computes cut length for straight match, drop match or plain wallpaper, adds a 10cm trim and toggles a 10% spare buffer.

Wallpaper Resolution Matcher

Work out the ideal wallpaper size and aspect ratio from your monitor resolution, with combined sizes for dual and triple multi-monitor spans.

Webhook Signature Verifier (HMAC)

Computes HMAC-SHA256/512/SHA-1 via Web Crypto, strips sha256= or v1= prefixes by regex, diffs character by character.

Wedding Place Card Maker

Turn a guest list into A4 6-up place card sheets with fold and cut guides, exported as high-res PNG.

VTuber Stream Schedule Image Maker

Set per-day titles, start/end times, off-day toggles, upload an avatar, pick from 8 themes and export a 1280x720 PNG.

Weibull Distribution Probability Calculator

Enter shape k (0.05-20), scale lambda (0.01-1000) and x to read Weibull PDF, CDF, mean, median, mode and standard deviation as six values in one panel.

Wheel Offset & Clearance Calculator

Compare current and new rim width (J) and offset (mm) to see fender protrusion and inner suspension clearance in mm.

White Background Validator

Scan every pixel and flag anything but pure #FFFFFF, then show purity ratio and a non-white heatmap.

White Noise Player

Generate White, Pink and Brown noise via Web Audio API with 15/30/60-minute timer and exponential fade.

WiFi Instruction Card Maker

Generate Wi-Fi guest cards with embedded QR from SSID and password. Three templates, 800x560px PNG export.

Wilks Score Calculator

Turn your bodyweight and total lifted into a Wilks score to compare powerlifting strength across weight classes, using the 1994 sex-specific coefficients.

Handwritten Will Layout Calculator

Estimate page count and final line for handwritten Japanese wills from chars per line and lines per page.

Wilson Score Confidence Interval Calculator

Compute the Wilson score confidence interval for a binomial proportion. Bounds stay within 0 to 1 even with small samples or rates near 0% or 100%.

Car Window Tint VLT Calculator

Multiply glass VLT by film VLT to check if your car window tint meets Japan's 70% legal limit on front and side windows.

Wire Voltage Drop Calculator

Find single- or three-phase voltage drop, drop percent, load-end voltage and power loss from gauge, length and current across 13 copper or aluminum sizes.

WOFF2 Base64 Font Embedder

Encodes a .woff2 to base64 in the browser and outputs a paste-ready @font-face with inline src: url(data:font/woff2;base64,…). One font HTTP removed.

Plywood Cut Plan Generator

Enter board, kerf and parts to compute yield via a Maximal Rectangle bin packer with rotation and export as PNG.

Word Frequency Counter

Keyword frequency counter: rank word occurrences from any text with stop-word filtering, tag cloud, CSV export.

World Clock & Time Travel Slider

Add IANA cities in analog or digital and drag the ±24h slider to sync all cards and find the best meeting time globally.

Wraps Per Inch Yarn Weight Calculator

Identify the Craft Yarn Council weight of any yarn from its wraps per inch. Maps your WPI across the 7 standard weights, Lace to Super Bulky, with needles.

Writing Monotony Checker (Japanese desu/masu)

Detect Japanese sentence-ending monotony (desu/masu etc.), score it, and highlight endings repeating too often.

X Show More Breakpoint Previewer

Preview the Show More cutoff for X posts using DOM line measurement, mobile 5 lines and desktop 25 lines.

YAML JSON Converter

Bidirectional YAML and JSON conversion via js-yaml with 150ms debounce and inline syntax error overlay.

Yarn Strand Holding Calculator

Estimate combined yarn weight and needle size from CYC weight 1-7 and 2-10 strands via WPI cross-section sum.

Yarn Substitution Calculator

Find how many skeins of substitute yarn a pattern needs by yardage alone. Original skeins times yards per skein, divided by the new yardage, rounded up.

Yeast Pitch Rate Calculator

Calculates the yeast cell count your wort needs from volume and original gravity, using 0.75 for ales and 1.5 for lagers, with the pack count too.

YouTube End Card Layout Simulator

Drag 615x346 video and 300x300 circular subscribe frames on 16:9 background in 1800x840 safe area; export 1920x1080.

YouTube Thumbnail Preview

Test your thumbnail across YouTube's real Home, Sidebar and Mobile search layouts before uploading to lift CTR.