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遅延損害金計算機（商事・民事法定利率対応）
遅延損害金計算機（商事・民事法定利率対応）
Weekly Schedule Generator
Create beautiful stream schedules for VTubers.
Unit Converter
Convert data storage units (GB/MB/KB).
Password Generator
Generate secure passwords locally.
Case Converter
Convert text case (upper, lower, etc).
Duplicate Remover
Remove duplicate lines and sort.
Text Cleaner
Remove extra spaces and empty lines.
Base64 Converter
Encode/Decode Base64.
Lorem Ipsum Generator
Generate dummy text.
JSON Formatter
Format and validate JSON.
UUID Generator
Generate random UUIDs.
URL Encoder
Encode/Decode URLs.
HTML Entity Encoder
Escape special characters.
Date Difference
Calculate days between dates.
Age Calculator
Calculate age from birthdate.
Percentage Calculator
Calculate percentages.
BMI Calculator
Calculate Body Mass Index.
Unix Timestamp
Convert Epoch/Date.
QR Code Generator
Create QR codes.
Color Converter
HEX, RGB, HSL converter.
Stopwatch
Stopwatch with laps.
Dog Age Calculator
Convert dog years to human years.
Cat Age Calculator
Convert cat years to human years.
Japanese Era Converter
Convert Western years to Japanese Eras.
Discount Calculator
Calculate sale price and savings.
Aspect Ratio Calculator
Calculate dimensions based on ratio.
AI Prompt Builder
Build structured prompts for ChatGPT, Claude, and Image AI.
Pomodoro Timer
Focus timer for productivity.
Text Diff Checker
Compare two texts side-by-side to highlight additions, deletions, and changes instantly.
Base64 Image Viewer
Instantly decode Base64 strings to images or convert images to Base64 code.
Bill Splitter & Settlement
Calculate fair splits with weighted ratios and optimize 'who owes whom' settlements.
Box Breathing Guide
Calm your mind and improve focus with animated breathing exercises used by Navy SEALs.
Box Shadow Generator
Create beautiful layered CSS box shadows with real-time preview and multi-layer support.
BPM Tapper
Measure song tempo (BPM) by tapping your keyboard or screen in rhythm.
chmod Calculator
Visually set Linux file permissions and generate chmod commands in octal or symbolic format.
Contrast Ratio Checker
Check color contrast ratio against WCAG guidelines for web accessibility.
DnD Dice Roller
A polyhedral dice roller for TRPGs like D&D. Supports d4 to d20 with custom modifiers and history.
Dummy Data Generator
Generate realistic mock data (JSON, CSV, SQL) for development and testing.
File Hash Calculator
Calculate MD5, SHA-1, SHA-256, and SHA-512 hashes locally. Verify file integrity with chunked processing for large files.
AI Token Estimator
Quickly estimate token counts for GPT-4 and other LLMs. No API required.
Gym Interval Timer
A customizable interval timer for HIIT, Tabata, and circuit training with visual and audio cues.
.htpasswd Generator
Securely generate .htpasswd entries for Basic Authentication using Bcrypt, MD5, or SHA-1.
Daily Hydration Calculator
Calculate your ideal daily water intake based on weight, activity, and climate with a visual goal tracker.
Investment Simulator
Calculate compound interest growth with monthly contributions and tax considerations.
IP Subnet Calculator
Calculate network address, broadcast, and host range with visual CIDR and binary breakdown.
JSON to CSV Converter
Quickly convert JSON data to CSV format with nested object flattening and real-time validation.
JWT Payload Viewer
Instantly decode and view the contents of JSON Web Tokens (JWT) without verification.
Kaomoji Picker
Browse and copy Japanese emoticons (kaomoji) by category. One-click copy with history and search.
Keyboard Ghosting & NKRO Tester
Check your keyboard for ghosting and N-key rollover with this real-time visualizer.
Loan & Mortgage Simulator
Calculate monthly repayments, total interest, and see an amortization schedule for your home or car loan.
Global Meeting Planner
Find the perfect meeting time across multiple time zones with visual business hour overlaps.
Metronome
An accurate, high-precision metronome with adjustable BPM, time signatures, and subdivisions.
Morse Code Translator
Translate text to Morse code and back. Features real-time conversion, sound (beep), and screen flash signals.
Image Palette Extractor
Extract beautiful color palettes from any image instantly. Get HEX, RGB, and HSL codes for your design projects.
Pixel Art Editor
A simple online tool to create retro pixel art, manage frames, and export as PNG or Sprite Sheets.
PPI Calculator
Calculate Pixels Per Inch (PPI) and dot pitch to check display sharpness.
Regex Explainer & Tester
Visualize and test regular expressions in real-time with step-by-step explanations.
Roman Numeral Converter
Easily convert between Arabic numbers and Roman numerals with step-by-step explanations.
Speech Time Estimator
Calculate reading time for your script based on word and character count. Perfect for presentations.
SQL Formatter
Prettify messy SQL queries with proper indentation and dialect support.
SVG Optimizer
Optimize and shrink SVG files by removing metadata and unnecessary code.
SVG Placeholder Generator
Create customizable SVG placeholder images for web development and design mockups.
TDEE & Macro Calculator
Calculate your Total Daily Energy Expenditure (TDEE) and optimal PFC balance for your fitness goals.
Online Tone Generator
Generate pure tones, sweep frequencies, and test your audio equipment with various waveforms.
User-Agent Analyzer
Instantly parse and analyze User-Agent strings to identify Browser, OS, and Device details.
VAT/Sales Tax Calculator
Calculate tax-inclusive and exclusive prices with invoice-ready rounding options.
White Noise Player
Boost focus and sleep with White, Pink, and Brown noise. Features a sleep timer and smooth fade-out.
Aim Trainer
Boost your clicking accuracy and reaction time with this customizable mini-game.
Fancy Border Radius Generator
Create organic, blob-like shapes using 8-point CSS border-radius. Preview and copy CSS code instantly.
Bra Size Calculator
Calculate your bra size (JP/US/UK) based on underbust and topbust measurements with sister size advice.
CHMOD Symbolic Converter
Instantly convert between CHMOD numeric (755) and symbolic (rwxr-xr-x) permissions.
Click Speed Test (CPS)
Test your clicking speed in 1, 5, 10, or 60 seconds. See your CPS, rank, and click distribution graph.
Color Blindness Simulator
Simulate how images appear to people with different types of color vision deficiencies.
Cookie Parser
Parse, decode, and edit browser cookie strings into a readable table or JSON format.
CSV to JSON Converter
Easily convert CSV data to JSON format with type inference and header detection.
Cursive Text Generator
Instantly convert standard English text into elegant cursive (mathematical script) Unicode characters.
Decision Wheel
A customizable roulette wheel to help you make decisions quickly. Add options, set weights, and spin!
Bubble Level & Compass
Check tilt angles and cardinal directions using your smartphone's built-in sensors.
Multi-Discount & Tax Calculator
Calculate final prices with multiple discounts (e.g., 20% + 10% off) including sales tax.
Pregnancy Due Date Calculator
Calculate your estimated due date, current week, and fetal size based on your last period.
Electricity Cost Calculator
Calculate the electricity cost of household appliances based on power consumption and usage time.
Emoji Converter (Emojify)
Turn your text into fun messages with emojis! Replace words or append icons instantly.
Fuel Cost Calculator
Calculate trip fuel costs, split expenses with passengers, and compare car efficiency.
Git Command Generator
Select what you want to do and generate the perfect Git command instantly.
Glitch Image Generator
Create aesthetic glitch art with RGB shift, noise, and slicing effects.
Image Histogram Analyzer
Analyze image exposure, color distribution, and clipping with real-time gamma correction.
JSON Diff Checker
Compare two JSON objects and visualize differences (additions, deletions, and changes) in a tree view.
JWT Debug Generator
Generate dummy JWTs for development and debugging with custom payloads and secret keys.
Keyboard Event Viewer
Check JavaScript keyboard event properties (key, code, which) in real-time.
Markdown Previewer
A real-time Markdown editor with GitHub-style preview and HTML export.
1RM Calculator & Plate Loader
Calculate your one-rep max (1RM) and see a visual guide for loading plates.
Ovulation Calculator
Predict your most fertile days and ovulation date with a printable calendar.
Port Checker & Dictionary
A quick reference and search tool for common network port numbers and services.
Random Number Picker
Pick one or multiple random numbers from a custom range with animation.
Reaction Time Test
Measure your reflexes in milliseconds. Test your response speed for gaming or daily alertness.
English Readability Checker
Analyze English text readability using Flesch-Kincaid and Gunning Fog scores with word highlighting.
Ring Size Converter & Ruler
Convert ring sizes across JP, US, UK, and EU standards. Includes an on-screen ruler with calibration for accurate measurement.
ROT13 & Caesar Cipher Tool
Encrypt and decrypt text by shifting letters. Supports ROT1 to ROT25.
Screen & Window Info
Check screen resolution, window size, and device pixel ratio in real-time.
Sleep Cycle Calculator
Calculate the best time to wake up or go to bed based on 90-minute sleep cycles.
Stereo Tester
Check your speaker or headphone balance, phase, and frequency response instantly.
Tip Calculator
Calculate tip and split the bill easily with rounding options.
Vibration Tester
Test your smartphone's vibration motor and create custom patterns.
Visual Countdown Timer
A visual timer that shows remaining time with a shrinking pie chart and changing colors.
World Clock & Time Zone Converter
Check current times worldwide and simulate time differences with a slider. Perfect for global meetings and travel planning.
YAML ↔ JSON Converter
A real-time, bidirectional YAML and JSON converter with syntax validation and formatting.
ASCII Table & Search
Quickly lookup ASCII codes (Decimal, Hex, HTML Entities) and control characters with real-time filtering.
Aspect Ratio Calculator Pro
Calculate aspect ratios, pixel dimensions, and screen sizes from diagonal inches. Supports GCD simplification and common resolution presets.
Base64 File Converter
Convert any file (images, PDFs, fonts) to Base64 strings and back to files instantly in your browser.
Binary Text Converter
Convert text to binary/hex and back with a matrix-style animation.
Visual BMI Calculator
Calculate BMI with a visual silhouette that changes as you adjust height and weight sliders.
Mindful Breathing Circle
A simple tool to help you relax and focus using rhythmic breathing animations.
CHMOD Permission Calculator
Visually calculate Unix/Linux file permissions with prose explanations and security warnings.
Color Mixer
Blend two colors and generate a smooth gradient palette with custom ratios and steps.
CSS Triangle Generator
A GUI tool to generate CSS triangle code using the border property hack.
Business Date Calculator
Calculate working days excluding weekends and holidays.
EXIF Viewer & Eraser
Extract camera metadata (EXIF) from images and download a clean version without private info like GPS.
Factorial, Permutation & Combination Calculator
Instantly calculate n!, nPr, and nCr with step-by-step expansion and support for large numbers.
GCD & LCM Calculator
Calculate the Greatest Common Divisor (GCD) and Least Common Multiple (LCM) for multiple numbers with step-by-step explanations.
HTTP Status Code Checker
Quickly lookup HTTP status codes, their meanings, causes, and solutions.
Japanese Era Converter
Convert Western years to Japanese eras (Reiwa, Heisei, etc.), calculate age (Full/Traditional), and generate a school history timeline.
Keyboard Cleaner & Lock
Safely clean your keyboard by temporarily disabling all keys. Features ripple effects and cat detection.
Kinetic Typography Generator
Animate text with Bounce, Shake, or Glitch effects and export HTML/CSS.
List Randomizer
Shuffle any list and split into groups instantly.
Meta Tag & OGP Analyzer
Analyze OGP, Twitter Cards, and SEO meta tags by simply entering a URL.
Visual Metronome
A soundless metronome that uses light and movement to guide your rhythm.
OGP Image Simulator
Preview how your OGP images appear on X (Twitter), Facebook, LinkedIn, and Discord.
Password Strength Checker
Check the security of your password instantly and get tips to improve it.
Percentage Change & Discount Calculator
Calculate percentage change, growth rate, and discounts with simple sentence-based results.
PFC Balance Calculator
Calculate your ideal protein, fat, and carbohydrate intake in grams based on your daily calorie goal.
Pomodoro Focus Tracker
A productivity timer that tracks focus sessions, task names, and total work time.
Prime Number Checker
Check if a number is prime, perform prime factorization, and find nearest primes.
Scientific Notation Converter
Quickly convert between decimal numbers and scientific (E) notation with significant figure control.
Subnet Mask Cheat Sheet & Calculator
A handy reference for CIDR, subnet masks, and host counts, featuring a real-time subnet calculator.
Text Case Randomizer
Convert text to Random Case, Alternating Case, and Mocking Spongebob meme style.
Text Encryption Tool
Encrypt and decrypt text using AES with a password. Secure, browser-based, and no data is sent to the server.
Text Repeater
Instantly repeat any text for test data or design mockups.
Time Duration Calculator
Calculate duration between two times or add multiple time durations easily.
Unicode Escape Converter
Convert text to Unicode escape sequences (JS, CSS, HTML) and back instantly.
Unit Price Calculator
Compare prices of multiple products by weight or volume to find the best deal.
Word Frequency Counter
Analyze text to count word occurrences and visualize them in a tag cloud.
YouTube Thumbnail Preview
Preview your YouTube thumbnails in real layouts (Home, Sidebar, Mobile) to optimize CTR.
A11y Contrast Checker
Check text contrast ratios against WCAG AA and AAA standards for web accessibility.
Reverse Text Generator
Instantly flip your text backwards. Perfect for social media, riddles, or checking palindromes.
Syllable Counter
Count the number of syllables in your English text instantly for poetry, lyrics, and speechwriting.
Text Art Generator
Transform your text into stylish art with shadows and gradients for web and design.
English Text Inflector
Automatically convert English words between plural, singular, and past tense forms using linguistic rules.
Text Shortener
Extracts key sentences to summarize long texts quickly.
Keyword Extractor & Summarizer
Quickly extract key terms and generate a logic-based summary from any text.
Voice to Text Converter
Transcribe your voice into text in real-time. Perfect for notes, meeting minutes, and hands-free drafting.
Academic Paper Title Generator
Generate professional, catchy academic paper titles from your research keywords instantly.
Email Subject Line Analyzer
Analyze your email subject lines to improve open rates with sentiment and keyword insights.
Legal Jargon Simplifier
Converts complex legal terms into plain, everyday language to help you understand contracts and documents.
Presentation Script Summarizer
Condense your presentation scripts into key points and highlight essential keywords instantly.
Product Description Generator
Create compelling product copy and SEO-friendly descriptions instantly.
Resume Keyword Extractor
Extract and compare keywords from your resume and job descriptions to optimize for ATS.
Social Media Bio Generator
Generate attractive SNS bios from keywords to increase followers.
Text Tone Analyzer
Analyze the sentiment, formality, and humor of your text to ensure perfect communication.
URL Slug Generator
Convert titles and text into SEO-friendly URL slugs. Supports Romanization and stop-word removal.
Character-Level Diff Checker
Compare two texts character by character to find exact differences and changes.
Reverse BMI Calculator
Calculate target weight from your desired BMI. Supports Metric and Imperial units.
Benham's Disk Simulator
A scientific optical illusion top that creates colors from black and white.
E-commerce White Background Validator
A browser-based e-commerce white background validator tool. No data sent to server.
Plywood Cut Plan Visualizer
A browser-based plywood cut plan visualizer tool. No data sent to server.
Video Subtitle CPS Checker
A browser-based video subtitle cps checker tool. No data sent to server.
SSH ProxyJump Config Generator
A browser-based ssh proxyjump config generator tool. No data sent to server.