This ring size chart matches US ring sizes to the inside diameter and circumference in millimetres. Measure a ring that fits, then match the diameter below. Sizes are approximate and vary by maker.
| US size | Diameter (mm) | Circumference (mm) |
|---|---|---|
| 4 | 14.8 | 46.5 |
| 5 | 15.7 | 49.3 |
| 6 | 16.5 | 51.9 |
| 7 | 17.3 | 54.4 |
| 8 | 18.1 | 57.0 |
| 9 | 19.0 | 59.5 |
| 10 | 19.8 | 62.1 |
| 11 | 20.6 | 64.6 |
| 12 | 21.4 | 67.2 |
| 13 | 22.2 | 69.7 |
Note: approximate; check the jeweller’s own chart for exact sizing.