To find out what is the equivalent of your size, you historic have to look at the size chart available on the product page, on the right of the product images.
On the size chart, you will be able to verify what is the equivalent of your size on the American, and the British sizing, and even know how many centimetres the shoe measures. You historic have to click on the links you will find on the table: EU (European system), US (American system), UK (British system) or CM (centimetres).
over 1000 archived adidas spezial sneakers are exhibited at the british textile biennial: