Inside Circumference (mm) UK, Ireland, Australia & New Zealand Size United States & Canada Size
40.4 C 1 1/2
41 C 1/2 1 3/4
41.7 D 2
42.3 D 1/2 2 1/4
42.9 E 2 1/2
43.6 E 1/2 2 3/4
44.2 F 3
44.8 F 1/2 3 1/4
45.5 G 3 1/2
46.1 G 1/2 3 3/4
46.8 H 4
47.4 H 1/2 4 1/4
48 I 4 1/2
48.7 J 4 3/4
49.3 J 1/2 5
50 K 5 1/4
50.6 K 1/2 5 1/2
51.2 L 5 3/4
51.9 L 1/2 6
52.5 M 6 3/4
53.1 M 1/2 6 1/2
53.8 N 6 3/4
54.4 N 1/2 7
55.1 O 7 1/4
55.7 O 1/2 7 1/2
56.3 P 7 3/4
57 P 1/2 8
57.6 Q 8 1/4
58.3 Q 1/2 8 1/2
58.9 R 8 3/4
59.5 R 1/2 9
60.2 S 9 1/4
60.8 S 1/2 9 1/3
61.4 T 9 3/4
62.1 T 1/2 10
62.7 U 10 1/4