Please choose size based on your foot length. 22cm foot length = US 4.5 size. 22.5cm foot length = US 5size. 23cm foot length = US 6size. 23.5cm foot length = US 6.5size. 24cm foot length = US 7.5size. 24.5cm foot length = US 8.5size. 25cm foot length= US 9size. 25.5cm foot length = US 9.5 size. 26cm foot length = US 10size. 26.5cm foot length = US 10.5size. Wide feet and fat feet, please choose one bigger size.