Sock size '9 to 11' fits a men's shoe sized 4 to 9 and a women's shoe sized 3 to 8.

Sock size '10 to 13' fits a men's shoe sized 8 to 12 and a women's shoe sized 7 to 11.

Sock size '13 to 15' fits a men's shoe sized 13 to 16 and a women's shoe sized 12 to 14.