Ring size conversion table
| US size | Inner circumference (mm) | Internal diameter (mm) | EU size | UK size |
|---|---|---|---|---|
| 3 | 44.2 | 14.1 | 44 | F |
| 3.5 | 45.5 | 14.5 | 45 | G½ |
| 4 | 46.8 | 14.9 | 46 | H½ |
| 4.5 | 48 | 15.3 | 47 | I½ |
| 5 | 49.3 | 15.7 | 49 | J½ |
| 5.5 | 50.6 | 16.1 | 50 | K½ |
| 6 | 51.9 | 16.5 | 51 | L½ |
| 6.5 | 53.1 | 16.9 | 52 | M½ |
| 7 | 54.4 | 17.3 | 54 | N½ |
| 7.5 | 55.7 | 17.7 | 55 | O½ |
| 8 | 57 | 18.1 | 57 | P½ |
| 8.5 | 58.3 | 18.5 | 58 | Q½ |
| 9 | 59.5 | 18.9 | 59 | R½ |
| 9.5 | 60.8 | 19.4 | 60 | Yes½ |
| 10 | 62.1 | 19.8 | 62 | T½ |
| 10.5 | 63.4 | 20.2 | 63 | U½ |
| 11 | 64.6 | 20.6 | 64 | V½ |
| 11.5 | 65.9 | 21.00 | 65 | W½ |
| 12 | 67.2 | 21.4 | 67 | X½ |
| 12.5 | 68.5 | 21.8 | 68 | Z |
| 13 | 69.7 | 22.2 | 69 | - |