I am a huge fan of these little booties. I wear them at barre without my ballet flats, so I ordered a size small for my 7.5 street shoe size and they fit nice and snug. If I wanted to wear them with my flats, I'd probably try a size medium. They keep my feet and ankles warm and I LOVE THEM!!!!! I will order another pair so when these are in the wash, I'll have a clean pair in my dance bag. I will never be without them.