I originally ordered a 40 as I am almost always a size 9US, but there was so much extra room by my heal. I went down to 39 and the fit is much better. Still breaking them in...but super cute  and I am hoping that these will be great for a decent amount of walking. I cant walk a long distance in flip-flops as my feet get super sore. I was looking for a better alternative fo a  sandal.