Vibram FiveFingers Womens Lontra Fleece^Mesh^Neoprene FiveFingers are designed around the foot's measurement in inches. There is no real 100% translation between your US size and FiveFingers size. In order to find the right size, please measure both feet from heel to tip of longest toe with a ruler in inches. Take the longest measurement for your longest foot and refer to our women's size chart or men's size chart .