I wear a US 8 1/2. I have trouble buying boots considering my half sized foot. A 9 is usually too big and depending on the brand an 8 1/2 could be too small. I was skeptical about this particular boot, but decided to wing it after researching Euro sizes. I decided that I should probably go based on my ugg size since those can be tricky to shop for as well. I usually buy a women's size 8 in my uggs, and decided to do the same with these, and they fit perfectly! They hug my foot, but are not tight at all.