Method one (measure the length of the feet): Make sure feet are straight, not bent, or arched. The distance from the thumb to the heel, in centimeters.
Method two (measure the inner length): find a pair of shoes that fit your feet. Take out the distance between the insole from point A to point B. In centimeters,please mark carefully according to the picture The protruding part is not included in the length
The correct posture must be taken when measuring:
1: Stand with your feet parallel  cannot sit or squat
2: The weight is evenly divided among the legs after trimethylamine