Hi,Dear value customers!Please choose size according to the foot length, please do not use the insole length.
For example,if your foot length (Heel to Toe) is 25cm, please choose size 40 in this model.

Size 35    fit for foot length is 22.5cm
Size 36    fit for foot length is 23.0cm
Size 37    fit for foot length is 23.5cm
Size 38    fit for foot length is 24.0cm
Size 39    fit for foot length is 24.5cm
Size 40    fit for foot length is 25.0cm
Size 41    fit for foot length is 25.5cm