International Ring Size Chart
| Size mm | Diameter mm | British size | Australian size | French size | German size | Italian size | Swiss size | USA size | Japanese size |
|---|---|---|---|---|---|---|---|---|---|
| 48 | 15.27 | I 1/2 | I 1/2 | - | 15 1/4 | 8 | - | 4.5 | 8 |
| 49 | 15.7 | J 1/2 | J 1/2 | - | 15 3/4 | 9.5 | - | 5 | 9 |
| 51 | 16.1 | L | L | 51 3/4 | 16 | 10.5 | 11 3/4 | 5 1/2 | 11 |
| 52 | 16.51 | M | M | 52 3/4 | 16 1/2 | 11.5 | 12 3/4 | 6 | 12 |
| 53 | 16.92 | N | N | 54 | 17 | 13 | 14 | 6 1/2 | 13 |
| 55 | 17.35 | O | O | 55 1/4 | 17 1/4 | 14.5 | 15 1/4 | 7 | 14 |
| 56 | 17.75 | P | P | 56 1/2 | 17 3/4 | 16 | 16 1/2 | 7 1/2 | 15 |
| 57 | 18.19 | Q | Q | 57 3/4 | 18 | 17 | 17 3/4 | 8 | 16 |
| 58 | 18.53 | Q 1/2 | Q 1/2 | 58 | 18 1/2 | 18.5 | - | 8 1/2 | 17 |
| 59 | 18.89 | R 1/2 | R 1/2 | 59 1/4 | 19 | 19.5 | - | 9 | 18 |
| 61 | 19.41 | S 1/2 | S 1/2 | 60 1/2 | 19 1/2 | 21 | - | 9 1/2 | 19 |
| 62 | 19.84 | T 1/2 | T 1/2 | 61 3/4 | 20 | 22 | - | 10 | 20 |
| 63 | 20.2 | U 1/2 | U 1/2 | 62 3/4 | 20 1/4 | 23.5 | - | 10 1/2 | 22 |
| 65 | 20.68 | V 1/2 | V 1/2 | 64 1/4 | 20 3/4 | 25 | - | 11 | 23 |
| 66 | 21.08 | W 1/2 | W 1/2 | 66 | 21 | 26.5 | - | 11 1/2 | 24 |
| 68 | 21.49 | Y | Y | 67 1/2 | 21 1/4 | 27.5 | 27 1/2 | 12 | 25 |
| 69 | 21.89 | Z | Z | 68 3/4 | 21 3/4 | 28.5 | 28 3/4 | 12 1/2 | 26 |
| 70 | 22.33 | - | - | - | 22 | 30 | - | 13 | 27 |