The distance between your sign and its viewers is the number one factor in determining the type of LED display you will need. Longer distances require less resolution and shorter distances require higher resolutions. In addition, if you are traveling at 55 MPH on a freeway, and the sign is 600 feet away at a truck stop, the text letters must be at least 20 inches tall to be legible. Likewise, if you are standing 60 feet away from a street level sign, the letters need only be two inches tall to be legible.

The rule of thumb is that you need 1 inch for every 30 feet of viewing distance.