Buy shoes according to the length of the foot.Feet wide feet fat choose a bigger one size.
US size 4 = European size 35 =22.5 cm
US size 5 = European size 36 =23 cm
US size 6 = European size 37 =23.5 cm
US size 7 = European size 38 =24 cm
US size 8 = European size 39 =24.5 cm
US size 9 = European size 40 =25 cm