Letter size calculator — find the right letter height for your viewing distance
Sign Sizing Tool
What Size Letters Do You Need?
The information presented in this chart is based on lettering using the font Helvetica as black text on a white background in a composition using optimal negative space seen in natural lighting. This condition represents a sign with maximum legibility. Factors that would decrease the legibility of the sign are: font selection, color choice, lighting, negative space, and other environmental factors. Enter your viewing distance to find the right letter height — or pick a letter height to see how far it reads. Click any row in the table to select a size.
Viewing distance
100 ft
Recommended height
12"
Ideal up to
120 ft
Readable up to
525 ft
Common uses
| Height | Scale | Ideal distance | Max readable |
|---|
Data from the Pennsylvania Transportation Institute & USSC. Assumes block-style uppercase letters with optimal contrast. Script or thin-stroke fonts may reduce readable distance by 30–40% at the same height.
