Complete Conversion Table
This table provides the inside diameter in millimeters and its equivalent size in different regions.
| Inside Diameter (mm) | US / Canada | UK / Australia | Europe / ISO | Japan / China |
|---|---|---|---|---|
| 14.0 | 3 | F | 44 | 4 |
| 14.5 | 3.5 | G | 45.5 | 5 |
| 15.0 | 4 | H | 47 | 7 |
| 15.3 | 4.5 | I | 48 | 8 |
| 15.7 | 5 | J ½ | 49.5 | 9 |
| 16.1 | 5.5 | K ½ | 50.5 | 10 |
| 16.5 | 6 | L ½ | 51.5 | 11 |
| 16.9 | 6.5 | M ½ | 53 | 13 |
| 17.3 | 7 | N ½ | 54.5 | 14 |
| 17.7 | 7.5 | O ½ | 55.5 | 15 |
| 18.1 | 8 | P ½ | 57 | 16 |
| 18.5 | 8.5 | Q ½ | 58.5 | 17 |
| 19.0 | 9 | R ½ | 59.5 | 18 |
| 19.4 | 9.5 | S ½ | 61 | 19 |
| 19.8 | 10 | T ½ | 62.5 | 20 |
| 20.2 | 10.5 | U ½ | 63.5 | 21 |
| 20.6 | 11 | V ½ | 65 | 23 |
