Attention:1.Our shoes are not standard sizes , pleasedon"'"t choose size according to your country usual size !2.Please choose the correct size for your kids according to foot length and inside length. The method to measure the foot as follows.3.Forwide foot,please choose one size bigger.Tips:Inside length =foot length + 1 cm ~ 1.5 cmExample:If your kids foot length is 15.5cm, then add 1 cm ~ 1.5 cm, you need to choose the size which inside length is16.5cm~17 cm.Size Chart(1 inch = 2.54 cm)Size 21 =Inside length13cm, fit for foot length about12 cmSize 22 =Inside length13.5 cm, fit for foot length about 12.5 cmSize23 =Inside length14cm, fit for foot length about13 cmSize24 =Inside length14.5cm, fit for foot length about13.5 cmSize25 =Inside length15cm, fit for foot length about14 cmSize26 =Inside length15.6cm, fit for foot length about14.6 cmSize27 =Inside length16.2cm, fit for foot length about15.2 cmSize28 =Inside length16.8 cm, fit for foot length about15.8 cmSize29 =Inside length17.4cm, fit for foot length about16.4 cmSize30 =Inside length18cm, fit for foot length about17 cm