| Sizes |
Internal diameter |
Internal circumference |
UK, Ireland, Australia |
France |
Germany |
Swiss |
USA & Canada |
Japan |
inches |
mm |
inches |
mm |
| - |
- |
- |
- |
0 |
- |
0.458 |
11.63 |
1.44 |
36.5 |
| - |
- |
- |
- |
1/4 |
- |
0.466 |
11.84 |
1.46 |
37.2 |
| A |
- |
- |
- |
1/2 |
- |
0.474 |
12.04 |
1.49 |
37.8 |
| A 1/2 |
- |
- |
- |
3/4 |
- |
0.482 |
12.24 |
1.51 |
38.5 |
| B |
- |
- |
- |
1 |
1 |
0.490 |
12.45 |
1.54 |
39.1 |
| B 1/2 |
- |
- |
- |
1 1/4 |
- |
0.498 |
12.65 |
1.56 |
39.7 |
| C |
- |
- |
- |
1 1/2 |
- |
0.506 |
12.85 |
1.59 |
40.4 |
| C 1/2 |
- |
- |
- |
1 3/4 |
- |
0.514 |
13.06 |
1.61 |
41.0 |
| D |
41 1/2 |
13 1/2 |
1.5 |
2 |
2 |
0.522 |
13.26 |
1.64 |
41.7 |
| D 1/2 |
- |
- |
- |
2 1/4 |
- |
0.530 |
13.46 |
1.67 |
42.3 |
| E |
42 3/4 |
13 3/4 |
2 3/4 |
2 1/2 |
3 |
0.538 |
13.67 |
1.69 |
42.9 |
| E 1/2 |
- |
- |
- |
2 3/4 |
- |
0.546 |
13.87 |
1.72 |
43.6 |
| F |
44 |
14 |
4 |
3 |
4 |
0.554 |
14.07 |
1.74 |
44.2 |
| F 1/2 |
- |
- |
5 1/4 |
3 1/4 |
5 |
0.562 |
14.27 |
1.77 |
44.8 |
| G |
45 1/4 |
- |
- |
3 3/8 |
- |
0.565 |
14.36 |
1.78 |
44.9 |
| G 1/2 |
- |
14 1/2 |
6 1/2 |
3 5/8 |
6 |
0.573 |
14.56 |
1.80 |
45.6 |
| H |
46 1/2 |
- |
- |
3 3/4 |
- |
0.577 |
14.65 |
1.81 |
45.9 |
| H 1/2 |
- |
15 |
- |
4 |
7 |
0.585 |
14.86 |
1.84 |
46.5 |
| I |
47 3/4 |
- |
7 3/4 |
4 1/4 |
- |
0.592 |
15.04 |
1.86 |
47.1 |
| I 1/2 |
- |
15 1/4 |
- |
4 1/2 |
8 |
0.601 |
15.27 |
1.89 |
47.8 |
| J |
49 |
15 1/2 |
9 |
4 5/8 |
- |
0.610 |
15.49 |
1.92 |
48.7 |
| J 1/2 |
- |
15 3/4 |
- |
5 |
9 |
0.618 |
15.70 |
1.94 |
49.3 |
| K |
50 |
- |
10 |
5 1/8 |
- |
0.622 |
15.80 |
1.94 |
49.3 |
| K 1/2 |
- |
- |
- |
5 3/8 |
10 |
0.630 |
16.00 |
1.97 |
50.0 |
| L |
51 3/4 |
16 |
11 3/4 |
5 1/2 |
- |
0.634 |
16.10 |
1.98 |
50.3 |
| L 1/2 |
- |
- |
- |
5 7/8 |
11 |
0.646 |
16.41 |
2.02 |
51.3 |
| M |
52 3/4 |
16 1/2 |
12 3/4 |
6 |
12 |
0.650 |
16.51 |
2.04 |
51.8 |
| M 1/2 |
- |
- |
- |
6 1/4 |
- |
0.658 |
16.71 |
2.06 |
52.2 |
| N |
54 |
17 |
14 |
6 1/2 |
13 |
0.666 |
16.92 |
2.08 |
52.8 |
| N 1/2 |
- |
- |
- |
6 3/4 |
- |
0.682 |
17.32 |
2.14 |
54.4 |
| O |
55 1/4 |
17 1/4 |
15 1/4 |
7 |
14 |
0.69 |
17.53 |
2.17 |
55.1 |
| O 1/2 |
- |
- |
- |
7 1/4 |
- |
0.698 |
17.73 |
2.19 |
55.7 |
| P |
56 1/2 |
17 3/4 |
16 1/2 |
7 1/2 |
15 |
0.706 |
17.93 |
2.22 |
56.3 |
| P 1/2 |
- |
- |
- |
7 3/4 |
- |
0.714 |
18.14 |
2.24 |
57.0 |
| Q |
57 3/4 |
18 |
17 3/4 |
8 |
16 |
0.722 |
18.34 |
2.27 |
57.6 |
| Q 1/2 |
- |
- |
- |
8 1/4 |
- |
0.730 |
18.54 |
2.29 |
58.25 |
| R |
59 |
18 1/2 |
19 |
8 5/8 |
17 |
0.738 |
18.75 |
2.32 |
58.9 |
| R 1/2 |
- |
19 |
- |
8 7/8 |
18 |
0.746 |
18.95 |
2.34 |
59.5 |
| S |
60 1/4 |
- |
20 1/4 |
9 1/8 |
- |
0.752 |
19.10 |
2.36 |
60.0 |
| S 1/2 |
- |
- |
19 1/2 |
9 3/8 |
19 |
0.760 |
19.31 |
2.39 |
60.6 |
| T |
61 1/2- |
- |
21 1/2 |
9 5/8 |
- |
0.768 |
19.51 |
2.41 |
61.3 |
| T 1/2 |
- |
20 |
- |
10 |
20 |
0.781 |
19.84 |
2.45 |
62.3 |
| U |
62 3/4 |
- |
22 3/4 |
10 1/4 |
21 |
0.788 |
20.02 |
2.47 |
62.9 |
| U 1/2 |
- |
20 1/4 |
- |
10 1/2 |
22 |
0.794 |
20.17 |
2.49 |
63.4 |
| V |
63 |
- |
23 3/4 |
10 5/8 |
- |
0.800 |
20.32 |
2.51 |
63.8 |
| V 1/2 |
- |
20 3/4 |
- |
11 |
23 |
0.814 |
20.68 |
2.56 |
65.0 |
| W |
65 |
- |
25 |
11 1/8 |
- |
0.818 |
20.78 |
2.57 |
65.3 |
| W 1/2 |
- |
21 |
- |
11 3/8 |
24 |
0.824 |
20.94 |
2.59 |
65.8 |
| X |
66 1/4 |
- |
26 1/4 |
11 5/8 |
- |
0.834 |
21.18 |
2.62 |
66.6 |
| X 1/2 |
- |
- |
- |
11 7/8 |
- |
0.839 |
21.30 |
2.63 |
66.9 |
| Y |
67 1/2 |
21 1/4 |
27 1/2 |
12 |
25 |
0.846 |
21.49 |
2.66 |
67.5 |
| Z |
68 3/4 |
21 3/4 |
28 3/4 |
12 1/2 |
26 |
0.862 |
21.89 |
2.71 |
68.8 |
| Z 1/2 |
- |
- |
- |
12 3/4 |
- |
0.870 |
22.10 |
2.73 |
69.4 |
| - |
- |
22 |
- |
13 |
27 |
0.879 |
22.33 |
2.76 |
70.1 |
| Z1 |
- |
- |
- |
13 1/4 |
- |
0.882 |
22.40 |
2.77 |
70.4 |
| - |
- |
- |
- |
13 1/2 |
- |
0.890 |
22.61 |
2.80 |
71.0 |
| Z2 |
- |
- |
- |
13 3/4 |
- |
0.898 |
22.81 |
2.82 |
71.7 |
| Z3 |
- |
- |
- |
14 |
- |
0.906 |
23.01 |
2.85 |
72.3 |
| Z4 |
- |
- |
- |
14 1/2 |
- |
0.922 |
23.42 |
2.90 |
73.6 |
| - |
- |
- |
- |
15 |
- |
0.938 |
23.83 |
2.95 |
74.8 |
| - |
- |
- |
- |
15 1/2 |
- |
0.954 |
24.23 |
3.00 |
76.1 |
| - |
- |
- |
- |
16 |
- |
0.970 |
24.64 |
3.05 |
77.4 |
|