Ring Measurement
Ring Size
| UK/AUS RING SIZE | US/CAN RING SIZE | EU RING SIZE | INTERNAL DIAMETER (MM) |
| F 1/2 | 3 | 44 | 14.1 |
| G 1/2 | 3.5 | - | 14.5 |
| H 1/2 | 4 | 47 | 14.9 |
| I 1/2 | 4.5 | 48 | 15.3 |
| J 1/2 | 5 | 49 | 15.7 |
| K 1/2 | 5.5 | - | 16.1 |
| L 1/2 | 6 | 52 | 16.5 |
| M 1/2 | 6.5 | 53 | 16.9 |
| N 1/2 | 7 | 54 | 17.3 |
| O 1/2 | 8.5 | 58 | 18.5 |
| P 1/2 | 8 | 57 | 18.1 |
| Q 1/2 | 8.5 | 58 | 18.5 |
| R 1/2 | 9 | - | 19 |
| S 1/2 | 9.5 | 61 | 19.4 |
| T 1/2 | 10 | 62 | 19.8 |
| U 1/2 | 10.5 | 63 | 20.2 |
| V 1/2 | 11 | - | 20.6 |
| W 1/2 | 11.5 | 66 | 21 |
| X 1/2 | 12 | 67 | 21.4 |
| Z 1/2 | 12.5 | 67 | 21.4 |
| 13 | 70 | 22.2 |