Viewing Distance
in Feet
Minimum Required Letter
Height in Inches
100 ft 4″
250 ft 10″
360 ft
(city block)
16″
500 ft 22″
750 ft 33″
1000 ft 43″
1320 ft
(1/4 mile)
57″
Calculations based on externally (or naturally) lit sign with all upper case Helvetica letters utilizing optimal negative space. Factors that may affect required letter size are: color scheme, font selection, traffic and weather conditions, or sign standoff. This letter visibility chart has been made based upon information provided by Pennsylvania Transportation Institute, Penn State University and the United States Sign Council (USSC). c1998.