International Size Chart

 

Inside Diameter (mm) Inside Circumference (mm) US AU/UK
14.1 44.3 3 F
14.3 44.9 3.25 F.5
14.5 45.6 3.5 G
14.7 46.2 3.75 G.5
14.9 46.8 4 H
15.1 47.4 4.25 H.5
15.3 48.1 4.5 I
15.5 48.7 4.75 1.5
15.7 49.3 5 J
15.9 50 5.25 J.5
16.1 50.6 5.5 K
16.3 51.2 5.75 K.5
16.5 51.8 6 L
16.7 52.5 6.25 L.5
16.9 53.1 6.5 M
17.1 53.7 6.75 M.5
17.3 54.3 7 N
17.5 55 7.25 N.5
17.7 55.6 7.5 O
17.9 56.2 7.75 O.5
18.1 56.9 8 P
18.3 57.5 8.25 P.5
18.5 58.1 8.5 Q
18.8 59.1 8.75 Q.5
19 59.7 9 R
19.2 60.3 9.25 R.5
19.4 60.9 9.5 S
19.6 61.6 9.75 S.5
19.8 62.2 10 T
20 62.8 10.25 T.5
20.2 63.5 10.5 U
20.4 64.1 10.75 U.5
20.6 64.7 11 V
20.8 65.3 11.25 V.5
21 66 11.5 W
21.2 66.6 11.75 W.5
21.4 67.2 12 X
21.6 67.9 12.25 X.5
21.8 68.5 12.5 Y
22 69.1 12.75 Z
22.2 69.7 13 Z.5