I wear a 10 in every shoe so I bought the 40. They were so tight I had to send back. I got the 41 which is 10.5-11 and they are about right but still could use more room in the front. However, I decided to keep them. Aside from one toe on one foot that sort of hits the front, they are very good shoes. I bought these to wear to Vegas for a work trip. I wear heels at night but during the day with all the walking you need an awesome shoe. Even sneakers hurt after awhile. Not these. I wore them all over the place and my feet were fine. My legs and the rest of me tired out but my feet didn't hurt! I am going to try and stretch the one a bit to make a little more room. But I would highly recommend them. Just go up a size.