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