My husband wears a size 11 1/2 shoe. We purchased a 12. His toe hit the front of the slipper. We kept that size and ordered a 13 for size comparison. There seemed to be just a quarter of an inch difference between the soles of the two different sizes and his toe still touches. The slippers are inexpensive and we are keeping the 13, but we expected the larger size to give him the room he needed and it did not.
They are quite comfortable with good arch support and nice sole padding. Although many reviewers said that they stretch, he has not experienced that yet. He has worn them nonstop around the house for three days and he has seen no difference in fit. We have mostly carpeted floors and the sole does not catch or grab on the carpet as he walks.