I wear 10.5 women's. I ordered 9 in men's. They are a perfect fit and have a little extra room around my toes. I'm a nurse and walk 12 hr shifts on a busy medical/surgical unit. I like that they have adjustable back but I wear them as a clog. Holes on the sides are plenty for ventilation and don't make my feet sweaty.
Although these are comfortable I still couldn't wear them without my plantar fasciitis compression socks. I would highly recommend them in conjunction with these Crocks (I'll attach the photo and just fyi, I have medium for my foot size).