I have 3 pairs, each a different style, each a different size. Luckily the site tells me to order up or down. However my last were to run big, but they didn't have my size so ordered my normal, and they are perfect. I wear an 8, sometimes I am a 39, or 40 category, wish it were more consistent Love, love the comfort of this shoe. They are so comfortable that you don't know they are there. I have foot issues, but no pain in feet, arches , or legs I don't worry too much about getting a wrong size since online shoes is so goo about returns.