Dear Friends, When you order our children’s shoes,you should according to the insole length. (insole length=Foot Length+1cm) The US size is not standard,just convenient for you to do order. The comfortable length is the foot length add about 1cm. By the way,we’d like to tell you:our shoes are china brand,we just print china size on the shoe. Please choose the correct size. If you difficult to select correct size pls kindly contact us,we will 24 hours here. Have a nice day!