These Sorel's are my favorites!!  I've had Columbia's that were okay, but not real warm or comfortable for wearing the entire day.  Got these and haven't looked back...good bye Columbia's!  These run 1/2 to 1 size large.  I'm size 8.5 and bought size 8.5 knowing I wanted to allow room for my thick wool socks.  It worked out just right, the thick socks and extra room in the boots are the perfect combination.  Comfortable and warm all day long.  Definitely keepers!