Please make sure to confirm the size before purchasing.Not every pair of shoes is in standard sizes.The inner length of the shoes is measured manually, and there may be a reasonable error of about 0.5cm Regarding the selection of children's shoe sizes, please note the following: Most children's shoe sizes are based on manufacturer's standards and do not have a unified standard (different shoes of the same size may have different dimensions). Please measure the foot length. For summer models, it is recommended that foot length + 0.5cm = shoe inner length. For spring/autumn and winter models, it is recommended that foot length + 1cm = shoe inner length (the cm indicated after each size is the shoe's inner length) Size 21 inner length 13.5cm .22 size inner length 14cm .23 size inner length 14.5cm .24 size inner length 15cm .25 size inner length 15.5cm .26 size inner length 16cm .27 size inner length 16.5cm .28 size inner length 17cm .29 size inner length 17.5cm .30 size inner length 18 cm