I normally wear a 7 but ordered these in 7.5. They fit really well & comfortably. I have short wide feet (perfect size is probably a 6.5 WIDE, but 7's work for the most part). I think a 7 would have been too tight across the balls of my feet. I wore a 'normal weight' pair of socks and they didn't slip in the heel area. They kept my feet warm & dry without making me feel like I do when I wear my Bogs. Love the Bogs, but they're not exactly fashion forward. The Keens aren't either but they're definitely a step up in appearance. Great with jeans in cold and/or wet weather. HTH!