Size recommendation by measurement
Stand up straight on a hard surface with your heel against the wall, and a piece of blank paper placed under the 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. Repeat for the other foot. If foot sizes differ, use the longest foot as a guide.
Use a ruler to measure the heel-to-toe length you marked for each foot.