These slippers are fantastic. They are soft with an indoor/outdoor sole that is not painful if you tend to sit with your legs tucked under you as I do. They are wonderfully warm even on very chilly mornings. I normally wear between an 8.5 and a 9 and went with the 9. It is a wee bit large (I can fit a finger between my heel and the back of the slipper), but they don't slide around on your feet and I actually like the wiggle room. You can always wear them with a pair of socks to make them more snug.