I always wear a size 9M. These were too short and too narrow. And I have a very average width foot (even slightly narrow). My vote is size up! These are cute sandals but sadly I returned them.These shoes don't have 1/2 sizes. Since it's open in the back I figured I could do an 8 instead of a 9. That is often times what I do in the shoe store if I love a shoe. These- I should have gone up- now I cannot exchange them since I wore them and threw out the box. They are very expensive and don't fit right- it's very unfortunategood style and fitSomewhat snug, I expect the fit will become better after a few wearings. Very sparkly!!!???These are always my most comfortable sandals ever. Enjoy.I really loved the shoe, but there is something wrong with the manufacturer's making of the shoe, I ordered a 41 it was to tight, so I ordered a 42, I could not get my foot into the shoe completely. very dissatisfied with the shoe.I wanted to keep the shoe but no way I could ever wear it comfortably. So I returned it againShort length and the back strap was back too far on the foot, it felt like a full size too small. I would have loved to keep these but they were wrong in every way.Beautiful shoes and every time I wear them, I receive many compliments. So very happy with my purchase.