Because US shoe size and China shoe size is not completely equal, so the following shoe size is only for reference:(Best selection method: check foot length)
US 4 = EU 35 =foot length 22.5 cm
US 5 = EU 36 =foot length 23 cm
US 5.5 = EU 37 =foot length 23.5 cm
US 6 = EU 38 =foot length 24 cm
US 6.5 = EU 39 =foot length 24.5 cm
US 7 = EU 40 =foot length 25 cm
(All measurement in cm and please note 1cm=0.39inch)