Small: US Women 6-7.5, Men 4.5-6; Euro 37-38.5; UK Women 4.5-6.5, Men 5-5.5 * Medium: US Women 8-9.5, Men 6.5-8; Euro 39-41.5; UK Women 7-8.5, Men 6-7.5 * Large: US Women 10-11.5, Men 8.5-10; Euro 42-43.5; UK Women 9-10.5, Men 8-9.5 * X-Large: US Men 10.5-12; Euro 44-45.5; UK Men 10-12