I wear a 8 1/2, so I got a 9 and they barely cover my feet! They are comfortable, BUT start to squeak LOUDLY once your feet start to sweat. I'm hoping that once I break them in they'll stop squeaking, but if they don't, I've wasted my money.
They also have no
arch support, but then again I'm 9 months pregnant (due in 7 days, Mar 18).