How BIG must my sign be?

How LARGE MUST my sign be? What size sign will best convey my message? From how far will people be able to read my sign?

These are questions we often get asked. As a joke, we tend to advise clients that, as a rule of thumb, (a) the bigger the better and (b) the sign should be as large as your budget allows. (Please note this IS a joke and while it is valid for outdoor signs, is not always best for intimate signs, where too big becomes gaudy.)

In truth, if a sign NEEDS to be visible from a specific distance – because it is located on the side of the road or it will only be viewed from moving vehicles or the sign is some distance from the point where it will be read (to name three of many scenario’s), then there are some rough scientific calculations that can be used to calculate the height the text needs to be in order for the text to be visible from a specific distance, as well as from a distance at speed. Please remember, at best, these calculations are rough guide, as they do not take into account ALL factors that affect visibility, especially height above the viewer.

The table below has been adapted from information taken from For more in depth calculations, especially for measuring legible distance while driving, please visit

It is important to remember that the table below refers to LETTER height ONLY. This means that if you have multiple lines of text or multiple words or either of these combined with a logo, the SIZE of THE SIGN will change, with the dependent factor being the DISTANCE at which the TEXT must be legible.

legible sign distance

For assistance for any signs, especially when you need to calculate sign size in order to make the sign legible, please call #SignForce on + 27 (0) 11 440 7524 / 5 or email