| International Standard "ISO-8653" The inner circumference of the ring (mm) |
Japan and USA, UK, Hong Kong comparison | |||||
| Japan | Diameter (mm) | Inner circumference (mm) | USA | united kingdom | Hong Kong | |
| 41 | 1 | 13 | 40.8 | 1 | C. | |
| 42 | 2 | 13.3 | 41.9 | 2 | D. | |
| 43 | 3 | 13.7 | 42.9 | 2.5 | E. | |
| 44 | Four | 14 | 44.0 | 3 | F. | 6 |
| 45 | Five | 14.3 | 45.0 | 7 | ||
| 46 | 6 | 14.7 | 46.1 | 3.5 | G. | 8 |
| 47 | 7 | 15 | 47.1 | Four | H. | 9 |
| 48 | 8 | 15.3 | 48.2 | 4.5 | I | Ten |
| 49 | 9 | 15.7 | 49.2 | Five | J. | 11 |
| 50 | Ten | 16 | 50.3 | 5.5 | K. | 12 |
| 51 | 11 | 16.3 | 51.3 | 6 | L. | 13 |
| 52 | 12 | 16.7 | 52.4 | 6.5 | M. | 14 |
| 53 | 13 | 17 | 53.4 | 7 | N. | 15 |
| 54 | 14 | 17.3 | 54.5 | 7.5 | O | 16 |
| 55 | 15 | 17.7 | 55.5 | 8 | P. | 17 |
| 56 | 16 | 18 | 56.6 | 18 | ||
| 57 | 17 | 18.3 | 57.6 | 8.5 | Q. | 19 |
| 58 | 18 | 18.7 | 58.6 | 9 | R. | 20 |
| 59 | 19 | 19 | 59.7 | 9.5 | S. | twenty one |
| 60 | 20 | 19.3 | 60.7 | twenty two | ||
| 61 | twenty one | 19.7 | 61.8 | Ten | T. | twenty three |
| 62 | twenty two | 20 | 62.8 | 10.5 | U | twenty four |
| 63 | twenty three | 20.3 | 63.9 | 11 | V. | twenty five |
| 64 | twenty four | 20.7 | 64.9 | 11.5 | W. | 26 |
| 65 | twenty five | twenty one | 66.0 | 12 | X | 27 |
| 66 | 26 | 21.3 | 67.0 | 12.5 | Y | 28 |
| 67 | 27 | 21.7 | 68.0 | 13 | Z. | 29 |
