Please notice that the size above is inner length. And there maybe 0-1cmerror due to the measure by hand. The size you need=length of your child's feet+1~2cmPlease choose the bigger size for the children feet grow very fast.
US size 12.5=CN size 30(shoes inner length 17.9cm) US size 13.5=CN size 31(shoes inner length 18.5cm) US size 1=CN size 32(shoes inner length 19cm) US size 2=CN size 33(shoes inner length 19.7cm) US size 3=CN size 34(shoes inner length 20.3cm) US size 3.5=CN size 35(shoes inner length 20.9cm) US size 4=CN size 36(shoes inner length 21.5cm) US size 5=CN size 37(shoes inner length 22.2cm) US size 6=CN size 38(shoes inner length 22.7cm) US size 7=CN size 39(shoes inner length 23.4cm)US size 7.5=CN size 40(shoes inner length 23.9cm)