The size is based on the U.S size standard.

SizeU.S)

Circumference

(mm)

Euro

Japan Hong Kong Switzerland
5 49.3½ 3.54 4.33 3.94
6 51.9 ½ 4.72 5.12 12¾
7 54.4 O 5.51 6.3 15¼
8 57 Q 6.3 7.09 17¾
9 59.5 S 7.09 7.87 20¼
10 62.1 7.87 8.66 21½
11 64.6 9.06 9.84 9.84
12 67.2 Y 9.84 10.63 27½
13 70 0 0 0 0
14 72.8 0 0 0 0