Sonic 14 - 'Monsters University'

Stand up straight on a hard surface with your heel against the wall and a piece of blank paper taped to the floor, flush against the wall beneath your foot.

Have someone mark the longest part of your foot (referred to as heel-to-toe length) on the paper with a pen or pencil, or measure yourself if necessary. Repeat with the other foot, as right and left sizes may be different.

Use a ruler to measure the heel-to-toe length you marked for each foot.