US to ISO Ring Size Chart
| US | UK | ISO |
|---|---|---|
| 3 | F | 44 |
| 3.5 | G | 46 |
| 4 | H | 47 |
| 4.5 | I | 48 |
| 5 | J | 49 |
| 5.5 | K | 51 |
| 6 | L | 52 |
| 6.5 | M | 53 |
| 7 | N | 54 |
| 7.5 | O | 56 |
| 8 | P | 57 |
| 8.5 | Q | 58 |
| 9 | R | 60 |
| 9.5 | S | 61 |
| 10 | T | 62 |
| 10.5 | U | 63 |
| 11 | V | 65 |
| 11.5 | W | 66 |
| 12 | X | 67 |
| 12.5 | Y | 68 |
| 13 | Z | 70 |
| 13.5 | Z1 | 71 |
| 14 | Z2 | 72 |
ISO sizes represent inner circumference in millimeters — the international standard for ring sizing.