Well, these slippers run at least a full size too small, if not more.  A size 10-11 should fit me with room to spare, I am a 9.5 -10 M, but these were painfully tight on me.  Fortunately my Mom has a size 8.5M & the slippers fit her perfectly.  Other than the major sizing problem, they are nice slippers, very cushy, decently constructed, & cute (& the reason for 2 stars.)