Lettering Size | Roadway Facing Signage | Calculating Board Feet

What size should my exterior signage lettering be?

signage from 20 feet

20 Feet

signage from 30 feet

30 Feet

signage from 70 feet

70 Feet

Letter Height Readable Distance for Maximum Impact Maximum Readable Distance
3″ 30′ 100′
4″ 40′ 150′
6″ 60′ 200′
8″ 80′ 350′
9″ 90′ 350′
10″ 100′ 450′
12″ 120′ 525′
18″ 180′ 750′
24″ 240′ 1000′
30″ 300′ 1250′
36″ 360′ 1500′
42″ 420′ 1750′
48″ 480′ 2000′
54″ 540′ 2250′
60″ 600′ 2500′

Note: The distance will vary approximately 10% with various colour combinations. Maximum distance is in colour RED or BLACK on a WHITE background. 5,280 feet equals one mile.

What if my store faces a roadway?

(Length of time letters are readable when moving)
Letter Height 30 MPH 40 MPH 60 MPH 80 MPH
6″ letters 1.4 seconds 1 second 0.7 seconds 0.5 seconds
8″ letters 1.8 seconds 1.4 seconds 0.9 seconds 0.7 seconds
12″ letters 3 seconds 2 seconds 1.5 seconds 1 seconds
18″ letters 4 seconds 3 seconds 2 seconds 1.5 seconds
24″ letters 5.5 seconds 4 seconds 2.75 seconds 2 seconds
36″ letters 8 seconds 6 seconds 4 seconds 3 seconds

Colour selection can dramatically increase readability, especially when at a distance.

How do I calculate board feet?

“Board Feet” Is a measurement of lumber volume. A board foot is equal to 144 cubic inches of wood. You can calculate the board footage using this formula.

(Thickness × Width × Length) / 144 = Board Feet

Note: Lumber is specified by its rough size. This is why a 1” × 4” board is actually 3⁄4” thick and a 2” × 4” board is actually 1 1⁄2” thick.

When you are figuring out board feet, keep in mind a waste factor. If you purchase good clear material add about 15% for waste. If you elect to use lower grade material you will have to allow for defects and more wasted material. Add about 30%.

calculating board feet comparison