How big should your letters be?
Enter how far away your reader is and who is reading. The calculator gives the smallest letters that still read and the size that really stands out, for storefront signs, banners, yard signs, and vehicle lettering.
Letter height calculator
The farthest spot where someone first needs to read it.
Planning figures for daylight. Bold capitals with strong contrast stay readable to about 30 feet per inch of letter height, and the sign trade’s rule for real impact is 1 inch per 10 feet. For drivers, the calculator adds the ground they cover while reading: about a second to notice the sign, then roughly 0.4 seconds a word. Lighting, viewing angle, and eyesight all move the number, so treat the minimum as the floor, not the goal. Want a second opinion on a layout? Send us the details.
The two numbers that matter
Every letter has two useful distances. Out to about 10 feet per inch of letter height, it grabs attention: that is the sign trade’s long-standing rule for real impact. Out to about 30 feet per inch, bold capitals with strong contrast can still be read in daylight, but only by someone who is already looking. The calculator shows both, so you can decide how hard the sign needs to work.
| Letter height | Real impact up to | Readable up to |
|---|---|---|
| 1 in | 10 ft | 30 ft |
| 2 in | 20 ft | 60 ft |
| 3 in | 30 ft | 90 ft |
| 4 in | 40 ft | 120 ft |
| 6 in | 60 ft | 180 ft |
| 8 in | 80 ft | 240 ft |
| 10 in | 100 ft | 300 ft |
| 12 in | 120 ft | 360 ft |
| 18 in | 180 ft | 540 ft |
| 24 in | 240 ft | 720 ft |
| 36 in | 360 ft | 1,080 ft |
| 48 in | 480 ft | 1,440 ft |
The chart assumes bold capitals, strong contrast, daylight, and a reader standing still. Letter height means the height of a capital letter.
What makes letters need to be bigger
- Thin, script, or decorative fonts. Fine strokes blur first. A script name can need half again the height of a bold one to read from the same spot.
- Weak contrast. Tone-on-tone color, or text laid over a busy photo, costs you distance fast. White on black and black on yellow read the farthest.
- Moving traffic. A driver has a few seconds, and covers a lot of ground while reading. At 45 mph a six-word message needs to read from about 225 feet farther away than the sign itself sits.
- More words. Every word you add has to fit in the same space, so every letter gets smaller. Cut words before you shrink letters.
Signs, banners, and vehicles
For a storefront sign or banner, measure from where people first need to read it, usually the road or the far side of the parking lot. For yard signs, it is the street in front of the house. On a work truck or van, the sides are read across a lane or a parking lot, 30 to 60 feet away, and the tailgate is read by the car stuck behind you. We size vehicle lettering for exactly those distances. Inside, a lobby sign is read from the front door, and dimensional letters on a feature wall from across the room.
Good to know.
Still curious? A quick message is the fastest way to a real answer.
Get a quoteWhat does letter height mean on a sign?
The height of a capital letter, from the baseline to the top of the letter. Lowercase letters are shorter, so a line set in lowercase needs a slightly bigger font to read from the same spot. When you compare quotes or proofs, compare capital heights.
Is one inch per ten feet the right rule?
It is the sign trade’s long-standing rule of thumb for letters that grab attention, and it is the real impact figure in the calculator. Letters stay readable well beyond that: about 30 feet per inch for bold capitals with strong contrast in daylight, which is the minimum figure. How far toward the minimum you go is a judgment call about how hard the sign has to work.
How big should the lettering be on a truck or van?
Work from the farthest distance that matters, usually across a parking lot or a lane of traffic. A company name read from 60 feet by people on foot needs about 2 inches at the bare minimum and 6 inches to stand out, and drivers passing at speed need more. Trucks that must carry a USDOT number have to display it so it can be read from 50 feet in daylight while the truck is parked, which bold 2-inch characters handle.
How big should a QR code be?
Plan on about 1 inch of code for every 10 inches of scanning distance, so a code people scan from 10 feet should be about 12 inches square. Past about 25 feet people will not walk up to scan, and nobody scans from a moving car, so on a vehicle a QR code belongs on the tailgate or the doors, for people standing nearby. Keep it dark on a light background and test it before it prints.
Want letters that read from the road?
Tell us where the sign or vehicle will be seen and what it needs to say. We will size the lettering and send a free quote, usually within one business day.