Typography on a sign is a different job from typography on a page. A page is read from 16 inches in good light by someone who chose to read it. A sign is read from across a street, through a windshield, at dusk, by someone who gave it a second and a half. Most of what makes a sign readable comes down to a few measurable choices about the letters.
Gogi Signs designs and builds signs across New Jersey and New York City, and the same nine typography rules come up on nearly every project. This guide gives each rule with the figure behind it, from the United States Sign Council, the Penn State legibility research and the ADA Standards, so you can check your own artwork before it goes to fabrication.
In this guide
Typography Tips at a Glance
Choose an Open, Sturdy Typeface
The typeface sets the legibility index, which is how many feet of viewing distance you get per inch of letter height. A Signs of the Times summary of the USSC research puts the range from about 20 for a serif face in all capitals lit from outside to 38 for a clean sans serif in mixed case in neon. The same 12 inch letters read from 240 feet in one and 456 feet in the other.
What makes a face “open” is large counters, the enclosed spaces in letters like a, e and o, and a generous x height, the height of the lowercase letters. Typeface designer Ralf Herrmann notes in his UCDA article on signage typefaces that purpose built signage faces share a large x height and open counters so they survive the halation of backlit and reflective signs. Helvetica, Futura, Franklin Gothic, Frutiger and similar faces all qualify. Decorative and novelty faces don’t.
Prefer Mixed Case for Words
All capitals look strong on a screen and lose distance on a wall. Mixed case words have a shape, with ascenders and descenders, that the eye recognizes before it reads the letters. The USSC research summarized by Signs of the Times found that all capital text needs about 15 percent more letter height to be legible from the same distance as upper and lower case. The Federal Highway Administration’s review of highway fonts found the same effect for road signs: mixed case improved word recognition compared with all capitals of the same height.
Use capitals for a short name of one or two words where you want a block shape. Use mixed case for anything longer, including taglines and addresses.
Get the Stroke Weight Right
Thin strokes disappear at distance and in low light. Heavy strokes close up the counters and the letters blur together, especially when lit. The Sign Research Foundation puts maximum readability at a stroke width about one fifth of the letter height. The ADA Standards set a range of 10 to 30 percent of the character height for visual characters, measured on the uppercase I. For a 12 inch letter that’s a stroke between 1.2 and 3.6 inches, with about 2.4 inches as the sweet spot.
Lit letters need extra care. Face lit channel letters glow a little past their edges, so a medium stroke reads as bold at night. Halo lit letters do the opposite: the glow is behind the letter and a thin stroke can look like a gap. Our illuminated vs non illuminated signs guide covers how lighting changes the design.
Give Letters Room
Tight tracking that looks sharp in a logo file turns into a smear at 200 feet. The ADA Standards set letter spacing at 10 to 35 percent of the character height and line spacing at 135 to 170 percent, and those ranges work well for exterior signs too. Lit letters need the wide end of the range because the glow fills the gaps. Fabricated letters also need physical room: each one has a return and a mounting pattern, and letters set too tight can’t be installed cleanly.
Avoid Heavily Condensed Faces
Condensed faces fit more words into the sign band, which is exactly the problem. The letters get narrow, the counters close and the legibility index falls. If the message doesn’t fit at a normal width, the answer is fewer words, not narrower letters. Our guide to choosing the right size for your business sign covers how message length and sign area trade off.
Use Scripts Carefully
A script can be the brand. It can’t be the only thing on the sign. Scripts have thin connecting strokes and small counters, so they sit near the bottom of the legibility range, and the ADA Standards exclude italic, oblique, script and highly decorative faces from visual characters on accessible signs altogether. The pattern that works is a script for the name, set large, with the category word in a sturdy sans serif below it: “Rosa’s” in script, “BAKERY” in block capitals.
Hand painted signs and carved signs are where scripts shine, because they’re read close up and the lettering is part of the craft. Our sister shop in New York collects examples in its storefront sign design ideas.
Build a Clear Hierarchy
A sign should have one thing to read first. The business name at full height, the category or tagline at about half, and the address or phone number at a third. More than three sizes reads as noise. Keep the sizes in one typeface family, or a script plus one sans serif, and never more than two families on a sign. The same order carries through a whole sign package: the big sign names the business, the blade sign repeats it, the window lettering gives the detail.
Make Numbers Legible
Address numbers are read by delivery drivers, emergency services and customers looking for the door, often at night. They need their own rules: a plain sans serif, never a script, with distinct forms for 1 and 7, 3 and 8, and 6 and 9. Four inches is a sensible minimum for a storefront number, and 6 inches for a building set back from the road. Many towns set their own minimum height for building numbers, so check the local rule before you size. Pixel Wraps, our sister graphics shop, applies the same distinct character rule to moving signs in its guide to designing vehicle graphics people can read in traffic.
Follow the Rules for Accessible Signs
Interior room signs, restroom signs and permanent space signs have to meet the ADA Standards, and the visual character rules read like a summary of this whole guide: conventional letterforms, no italic, script or decorative faces, stroke 10 to 30 percent of height, spacing 10 to 35 percent, line spacing 135 to 170 percent, a minimum of 5/8 inch for text read from under 6 feet, and a non glare finish with light on dark or dark on light contrast. Raised characters have a tighter set of rules, including sans serif only. Our guide to ADA sign requirements covers mounting heights, Braille and which signs need them, and our ADA signs page shows the products.
Typography Choices Compared
| Choice | Readable distance | Best use | Watch for |
|---|---|---|---|
| Open sans serif, mixed case | Longest | Main sign, road facing, lit letters | Can look plain without a logo mark |
| Sans serif, all capitals | About 15 percent shorter | Short names, blade signs | Needs extra spacing when lit |
| Slab or sturdy serif | Good | Traditional storefronts, carved signs | Thin serifs disappear at distance |
| Condensed sans | Shorter | Only when the band is very narrow | Closed counters, letters merge |
| Script | Shortest | The name on close range signs, paired with a sans | Never for the category word or the address |
| Decorative or novelty | Unpredictable | Interior feature walls | Not allowed on ADA signs |
A Typography Check for Any Sign
- The main typeface is an open sans serif or a sturdy serif.
- Words longer than two are in mixed case.
- Stroke width is roughly one fifth of the letter height, lighter for halo lit letters.
- Letter spacing is at least 10 percent of the height, more if lit.
- Nothing is condensed to make the message fit.
- Any script is the name only, paired with a sans serif category word.
- There are no more than three sizes and two typeface families.
- Address numbers are plain, distinct and at least 4 inches.
Then print it at full size, tape it up and read it from the sidewalk. Our sign design team does this on every job, and our guide to common sign design mistakes covers what else to look for.
Common Questions About Sign Typography
What is the most readable font for a business sign?
An open sans serif with a large x height in mixed case, such as Helvetica, Futura, Franklin Gothic or Frutiger. The USSC research puts clean sans serif faces at the top of the legibility range, roughly 30 to 38 feet of viewing distance per inch of letter height.
Should my sign be in all capitals?
Only for a short name of one or two words. For anything longer, mixed case reads from further away. All capital text needs about 15 percent more letter height to match the legibility of upper and lower case.
Can I use my script logo on my sign?
Yes, as the name, set large, with the category word in a plain sans serif beneath it. A script on its own sits at the bottom of the legibility range and is not permitted on ADA room signs.
How many fonts should a sign use?
One family, or a script plus one sans serif. Two families is the limit. Use size and weight within the family to build the hierarchy.
What size should address numbers be?
At least 4 inches on a storefront and 6 inches on a building set back from the road, in a plain sans serif with distinct number forms. Check your town’s building number rule, since many set their own minimum.
Do ADA signs require a specific font?
Not a named font. Visual characters must be conventional, not italic, script or decorative, with stroke 10 to 30 percent of height and spacing 10 to 35 percent. Raised characters must be sans serif and uppercase, with Braille below.
Make Your Sign Easy to Read
Send us your logo file and a photo of the building and we’ll set the typography for the viewing distance, check the stroke and spacing against the lighting, and show you a full size proof before anything is built. Request a free quote or see our sign design page for how we work.
Sources and further reading
