Inside Diameter Inside Circumference Sizes
MM Inches MM Inches UK/AU  US & Canada & Mexico France Germany & Russia & Ukraine & Asia India & China & Japan & South America Italy & Spain & Netherlands & Switzerland
14.05 0.553 44.14 1.74 F 3 44 14 4 4
14.25 0.561 44.77 1.76 F 1/2 3.25 44.625 14.25 4.5 4.625
14.45 0.569 45.4 1.79 G 3.5 45.25 14.5 5 5.25
14.65 0.577 46.02 1.81 H 3.75 45.875 14.75 6 5.875
14.86 0.585 46.68 1.84 H 1/2 4 46.5 15 7 6.5
15.04 0.592 47.25 1.86 I 4.25 47.125 15.25 7.5 7.125
15.27 0.601 47.97 1.89 I 1/2 4.5 47.75 15.5 8 7.75
15.53 0.611 48.79 1.92 J 1/4 4.75 48.375 --- 8.5 8.375
15.7 0.618 49.32 1.94 J 1/2 5 49 15.75 9 9
15.9 0.626 49.95 1.97 K 1/4 5.25 49.625 16 9.5 9.625
16.1 0.634 50.58 1.99 L 5.5 50.25 16.25 10 10.25
16.3 0.642 51.21 2.02 L 1/4 5.75 50.875 --- 11 10.875
16.51 0.65 51.87 2.04 M 6 51.5 16.5 12 11.5
16.71 0.658 52.5 2.07 M 1/2 6.25 52.125 16.75 12.5 12.125
16.92 0.666 53.16 2.09 N 6.5 52.75 17 13 12.75
17.13 0.674 53.82 2.12 N 1/2 6.75 53.375 --- 13.5 13.375
17.35 0.683 54.51 2.15 O 7 54 17.25 14 14
17.45 0.687 54.82 2.16 O 1/2 7.25 54.625 17.5 14.5 14.625
17.75 0.699 55.76 2.2 P 7.5 55.25 17.75 15 15.25
17.97 0.707 56.45 2.22 P 1/2 7.75 55.875 --- 15.5 15.875
18.19 0.716 57.15 2.25 Q 8 56.5 18 16 16.5
18.35 0.722 57.65 2.27 Q 1/2 8.25 57.125 18.25 16.5 17.25
18.53 0.729 58.21 2.29 Q 3/4 8.5 57.75 18.5 17 17.75
18.69 0.736 58.72 2.31 R 1/4 8.75 58.375 18.75 17.5 18.375
18.89 0.748 59.34 2.35 R 3/4 9 59 19 18 19
19.22 0.757 60.38 2.38 S 1/4 9.25 59.625 19.25 18.5 19.625
19.41 0.764 60.98 2.4 S 3/4 9.5 60.25 19.5 19 20.25
19.62 0.772 61.64 2.43 T 1/4 9.75 60.875 19.75 19.5 20.875
19.84 0.781 62.33 2.45 T 1/2 10 61.5 20 20 21.25
20.02 0.788 62.89 2.48 U 10.25 62.125 20.25 21 22.125
20.2 0.797 63.46 2.5 U 1/2 10.5 62.75 20.5 22 22.75
20.44 0.805 64.21 2.53 V 1/4 10.75 63.375 --- 22.5 23.375
20.68 0.814 64.97 2.56 V 1/2 11 64 20.75 23 24
20.85 0.821 65.5 2.58 W 1/4 11.25 64.625 --- 23.5 24.625
21.08 0.83 66.22 2.61 W 3/4 11.5 65.25 21 24 25.25
21.24 0.836 66.73 2.63 X 1/4 11.75 65.875 --- 24.5 25.875
21.49 0.846 67.51 2.66 Y 12 66.5 21.25 25 26.5
21.69 0.854 68.14 2.68 Y 1/2 12.25 67.125 21.5 25.5 27.125
21.89 0.862 68.77 2.71 Z 12.5 67.75 21.75 26 27.75
22.1 0.87 69.43 2.73 Z +1/2 12.75 68.375 --- 26.5 28.375
22.2 0.75 70 2.74 Z+1 13 69 22 27 29