International Ring Size Converter
| INSIDE DIAMETER | US/CAN | UK/AU | EUROPE | JAPAN |
|---|---|---|---|---|
| 15 mm | 4 | H | 46.5 | 7 |
| 15.3 mm | 4.5 | I | 48 | 8 |
| 15.6 mm | 5 | J | 49.5 | 9 |
| 16.2 mm | 5.5 | K | 50.5 | 10 |
| 16.6 mm | 6 | L | 52 | 11 |
| 16.9 mm | 6.5 | M | 53 | 13 |
| 17.2 mm | 7 | N | 54.5 | 14 |
| 17.8 mm | 7.5 | O | 55.5 | 15 |
| 18.1 mm | 8 | P | 57 | 16 |
| 18.5 mm | 8.5 | Q | 58 | 17 |
| 19.1 mm | 9 | R | 59.5 | 18 |
| 19.4 mm | 9.5 | S | 61 | 19 |
| 19.7 mm | 10 | T | 62 | 20 |
| 20.4 mm | 10.5 | U | 63.5 | 22 |
| 20.7 mm | 11 | V | 64.5 | 23 |