USA Europe UK inches cm
4.5 34.5 2 8.375” 21.3
5 35 2.5 8.5” 21.6
5.5 35.5 3 8.75” 22.2
6 36 3.5 8.875” 22.5
6.5 37 4.5 9.0625” 23
7 37.5 4.5 9.25” 23.5
7.5 38 5 9.375” 23.8
8 38.5 5.5 9.5” 24.1
8.5 39 6 9.6875” 24.6
9 40 6.5 9.875” 25.1
9.5 41 7 10 25.4
10 42 7.5 10.1875” 25.9
10.5 43 8 10.3215” 26.2
11 43.5 8.5 10.5” 26.7
11.5 44 9 10.6875” 27.1
12 44.5 9.5 10.875” 27.6