I bought the size 9-11, thinking they would fit like standard socks, but these are SOOOO small on my true size 8 feet, it was a struggle to get them to fit around my whole foot.  I forced them, though, only to find that they squish my toes together, are rough, scratchy and uncomfortable, and pop off your heel as soon as you start moving your foot around.  Maybe a bigger size would work better, but these are definitely not comfortable or practical.  Not worth the trouble of sending them back, so be forewarned; maybe a narrow size 7 shoe or smaller could wear these in this 9-11 size, but anything larger than that is going to have some issues.  I am sad, because I thought they would be just perfect with my cute Sperry Topsiders, which are just about the same color.