How Big Should Signage Text Be?

Ask how big text should be on a screen and you'll get a confident answer. Ask three sources and you'll get three. They differ by more than double, so it's worth knowing what's behind each.

What the sources say

• Daktronics says at least 1 inch of text height for every 25 feet of viewing distance, so a 4-inch character reads from about 100 feet.
• Western Michigan University's accessibility guidance gives 1 inch per 10 feet, with at least 3-inch lettering for important information.
• AVIXA uses a percentage of image height instead, with minimum element height running from 0.50% at a viewing ratio around 1 to 5.00% at a ratio of 9 to 10.
• The US Access Board's sign rules cover physical signs rather than screens: 5/8 of an inch under 6 feet of viewing distance, plus 1/8 of an inch per foot beyond that.

Why they differ

At 30 feet, about nine metres, Daktronics gives you 1.2 inches and Western Michigan gives you 3. They aren't really measuring the same thing. One is about the point where letters can just be made out on a bright sign. The other is about reading comfortably, for the widest range of eyesight.

What we'd use

For most signage, use the larger figure. The smaller rule is what you might get away with for a headline. Signage is read in passing, in bad light, by people who aren't trying, and anyone with weaker vision is left out if you design at the limit.

So take 1 inch per 10 feet as the working number for anything that has to be read, and the smaller rule as the absolute floor for anything else. In metric, that's about 2.5 cm of letter height for every 3 metres.

What else changes legibility

• Fewer words. A screen in a corridor gets a glance. A headline and one line is often all there's time for.
• Time on screen. Leave each state up for long enough to read it twice. Don't animate text in so slowly that the reader misses it.
• Weight and contrast. On LED, thin weights break up. Check it at your pixel pitch, and meet WCAG contrast at the very least.
• Height and angle. If it's overhead, people see it at an angle and it reads smaller than the numbers suggest.

Signage is usually a loop that nobody watches from the start, so the same advice applies as on a stand: every state stands alone. If that's what you're working on, see our digital signage page.