Ring Size Conversion — AU/UK → US with Diameter and Circumference (mm)
Ring Size Conversion (AU/UK to US)
| AU / UK | US | Diameter (mm) | Circumference (mm) |
|---|---|---|---|
| H | 4 | 14.88 | 46.8 |
| H½ | 4.25 | 15.09 | 47.4 |
| I | 4.5 | 15.29 | 48.0 |
| I½ | 4.75 | 15.49 | 48.7 |
| J | 5 | 15.70 | 49.3 |
| J½ | 5.25 | 15.90 | 49.9 |
| K | 5.5 | 16.10 | 50.6 |
| K½ | 5.75 | 16.31 | 51.2 |
| L | 6 | 16.51 | 51.8 |
| L½ | 6.25 | 16.71 | 52.5 |
| M | 6.5 | 16.92 | 53.1 |
| M½ | 6.75 | 17.12 | 53.8 |
| N | 7 | 17.32 | 54.4 |
| N½ | 7.25 | 17.53 | 55.1 |
| O | 7.5 | 17.73 | 55.7 |
| O½ | 7.75 | 17.93 | 56.3 |
| P | 8 | 18.14 | 57.0 |
| P½ | 8.25 | 18.34 | 57.6 |
| Q | 8.5 | 18.54 | 58.3 |
| Q½ | 8.75 | 18.75 | 58.9 |
| R | 9 | 18.95 | 59.5 |
| R½ | 9.25 | 19.15 | 60.2 |
| S | 9.5 | 19.35 | 60.8 |
| S½ | 9.75 | 19.56 | 61.4 |
| T | 10 | 19.76 | 62.1 |
| T½ | 10.25 | 19.96 | 62.7 |
| U | 10.5 | 20.17 | 63.4 |
| U½ | 10.75 | 20.37 | 64.0 |
| V | 11 | 20.57 | 64.6 |
| V½ | 11.25 | 20.78 | 65.3 |
| W | 11.5 | 20.98 | 65.9 |
| W½ | 11.75 | 21.18 | 66.6 |
| X | 12 | 21.39 | 67.2 |
| X½ | 12.25 | 21.59 | 67.8 |
| Y | 12.5 | 21.79 | 68.5 |
| Y½ | 12.75 | 21.99 | 69.1 |
| Z | 13 | 22.20 | 69.7 |
Notes: Measurements are approximate. For best results, measure at the end of the day and avoid sizing when hands are cold. If you are between sizes, the next half-size up is usually most comfortable.