I am a small 11.5 or a large 11, and these 11.5 fit quite snugly. You do not wear socks with them, and the toe box is snug. They are very flattering, because they do fit close, and they do not cut across my fourth toe like the New Balance Minimus. I have a smaller big toe and a more rounded foot than the more triangular type the Minimus is cut for, and these work well. They have decent arch support, too. A bonus, they come with black laces as spares!