sorry no one has replied and I'm not sure if I am qualified to respond. I normally wear around a 7. I have wide toes and might otherise size up to a 7.5 if I don't want pinching in certain shoes. In my Sidis, I wear a 38.5 in mens so that I can have a little more toe room as compared to the women's. You know I also take a little more room in my shoes because I don't like it when shoes fit like slippers. The man at the bike shop said that the men's and womens are the same and when they did not have my Sidi size in women's he switched me to the mens. I hope this in anyway helps.