I had previously bought a size 11 Old Friend slipper because one of the reviews said to buy one size bigger if you have a 1/2 size. WRONG! The 11's were too big, so this time I bought a size 10 for my 10 1/2 feet. Perfect with room to spare. Old Friend is the best made & most comfortable mocc/slipper I have ever had - period. That's it. Thanks!!!