Poster Font Size Calculator | Size Type for Reading Distance
Set a sheet format and how far away people read it, and get recommended point sizes for the title, subtitle, and body at once. Covers A0-B4 plus custom mm dimensions, with a layout preview so you can judge the result in one view.
💡 Check legibility before you commit the layout
The most common print mistake is designing a poster on a monitor 40-60 cm from your face, then discovering the body copy turns to mush from across the room. Readability does not depend on the raw point size; it depends on the ratio of letter height to viewing distance. The same 24 pt that reads fine at 1 m can be useless at 5 m. Designers who skip this step end up reprinting.
This calculator takes the format and the distance and assigns point sizes to three tiers — title, subtitle, and body — then draws them on the sheet so you can see how much space they claim. Settling the minimum body size for a given distance early means fewer layout do-overs later.
🧐 Frequently Asked Questions
How do I pick the viewing distance? Estimate where the nearest realistic reader stands. Wall and transit posters are usually read at 2-4 m, a desk-side A4 notice at 0.5-1 m, and a conference poster from the back rows at 6-10 m. When in doubt, size for the farthest reader to stay on the safe side.
How do points relate to millimeters? 1 pt equals about 0.353 mm (the DTP/PostScript point, 1/72 inch), and the tool shows this conversion in its note. A glyph's physical cap height is roughly the point value times 0.353 mm, and comparing that against the distance gives a working sense of legibility.
Isn't there a "5 mm per meter" sign rule? Road and safety signage often uses a standard of 5 mm cap height (4 mm lowercase) per meter of viewing distance, as in AS/NZS 1319. That figure targets instant glance recognition and tends to be oversized for body copy you actually stop and read. This tool returns a comfortable-reading baseline, so for signage meant to be grasped at a glance, scale the result upward.
What about academic conference posters? A common guideline is roughly 72 pt titles, 48-60 pt section headings, and 24-36 pt body, assuming people read it at 1-1.5 m. This tool, though, returns a minimum-legible floor, so the body usually comes out smaller than those comfort-oriented conventions. Treat 24-36 pt as a comfortable target and size up from the tool's minimum.
How large can custom sizes go? Width and height each accept 50-5000 mm, so oversized banners and non-standard panels still calculate as long as they fall inside that range.
📚 Why poster formats and points behave the way they do
ISO 216 A-series paper starts from A0 at one square meter and halves with each step, keeping a constant 1:√2 ratio between the long and short sides. That is why two A3 sheets tile exactly into an A2 and why scaling artwork up or down rarely distorts the type proportions. The point, meanwhile, is a leftover from metal type; the modern DTP point was standardized to 1/72 inch, about 0.353 mm, so a "12 pt" font no longer means the metal body it once did. Keeping your measurement units consistent between the design app and the printer avoids the classic surprise of a poster that looks fine on screen but prints a tier too small.