How do I know if my foot is narrow, medium or wide shoe size?

To measure foot width. Measure the flat width across the ball of your foot (the widest point) by stepping on the ruler or tape measure.

Women's Shoe Width Chart

Size narrow medium wide
5 2.8" 3.2" 3.55"
6 2.95" 3.3" 3.7"
7

3.05"

3.45" 3.8"
8
3.2" 3.55" 3.95"
9 3.3" 3.7" 4.05"
10 3.45" 3.8" 4.2"
11 3.55" 3.95" 4.3"
12 3.7" 4.05" 4.45"

Men's Shoe Width Chart

Size narrow medium wide
5
3.2"
3.4"
3.6"
 6
3.3"
3.5" 3.7"
 7
3.4"
3.6" 3.8"
8 3.5" 3.8" 3.9"
9 3.6" 3.9" 4.1"
10 3.8" 4.0" 4.2"
11 3.9" 4.1" 4.3"
12 4.0" 4.3"
4.4"