How to Measure Foot Dimensions
Shoe size is represented by length and ball girth in the Japanese Industrial Standard. The foot length and foot circumference of a human foot correspond to these two measurements respectively.
Foot measurements are taken with the subject standing barefoot and with weight distributed equally on both feet.
The distance between the Pternion (the rearmost point of the heel) and the tip of the longest toe is measured pararell to the foot axis. The foot axis is the line connecting the Pternion and the tip of the 2nd toe.
Foot circumference is measured with a tape so that the tape passes over the Metatarsale tibiale and the Metatarsale fibulare. The Metatarsale tibiale is the most medially prominent point on the head of the first metatarsal bone, and the Metatarsale fibulare is the most laterally prominent point on the head of the fifth metatarsal bone.