These fit snug on the hubby but I'm sure they will stretch out a bit. He wears a size 10 in most shoes, slippers, etc. and has a bit of a wide foot. We ordered the 9.5 - 10.5 size. If you like a bit more roominess to your slippers or wear socks with them or are on the larger end of this size, I would recommend going up to the next size.
I tried it on and it did feel nice and warm. The one thing I didn't like is that the tongue of the shoe at the top is attached at that point to the sides of the shoe. You can't bend it forward and it has no real give to it. If you have a thick foot or like a bit of loose fit there, this might not be the slipper for you.