Ring Size Guide
440showroom lists ring sizes using the Japanese sizing system. If you are located outside Japan, please use the conversion chart below to find your size. The range shown (-1 to 21) matches the sizes actually available in our catalogue.
| Japan | Diameter (mm) | Circumference / EU (mm) | US | UK/AU/NZ/SG | Hong Kong (ref.) | Taiwan (ref.) |
|---|---|---|---|---|---|---|
| -1 (P2) | 12.3 | 38.6 | — | — | — | — |
| 0 (P1) | 12.7 | 39.9 | — | — | — | — |
| 1 | 13.0 | 40.8 | 1 | C | 3 | 4 |
| 2 | 13.3 | 41.9 | 2 | D | 4 | 4 |
| 3 | 13.6 | 42.9 | 2½ | E | 5 | 5 |
| 4 | 14.0 | 44.0 | 3 | F | 6 | 6 |
| 5 | 14.3 | 45.0 | 3¼ | G | 7 | 6 |
| 6 | 14.6 | 46.1 | 3¾ | G–H | 8 | 7 |
| 7 | 15.0 | 47.1 | 4 | H–I | 9 | 8 |
| 8 | 15.3 | 48.2 | 4½ | I–J | 10 | 9 |
| 9 | 15.6 | 49.2 | 4¾ | J | 11 | 9 |
| 10 | 16.0 | 50.3 | 5¼ | K | 12 | 10 |
| 11 | 16.3 | 51.3 | 5¾ | L | 13 | 11 |
| 12 | 16.6 | 52.4 | 6 | L–M | 14 | 11 |
| 13 | 17.0 | 53.4 | 6¼ | M–N | 15 | 12 |
| 14 | 17.3 | 54.5 | 6¾ | N–O | 16 | 13 |
| 15 | 17.6 | 55.5 | 7¼ | O–P | 17 | 13 |
| 16 | 18.0 | 56.6 | 7½ | P | 18 | 14 |
| 17 | 18.3 | 57.6 | 8 | Q | 19 | 15 |
| 18 | 18.6 | 58.6 | 8¼ | R | 20 | 15 |
| 19 | 19.0 | 59.7 | 8¾ | S | 21 | 16 |
| 20 | 19.3 | 60.7 | 9 | T | 22 | 17 |
| 21 | 19.6 | 61.8 | 9½ | T–U | 23 | 17 |
This chart is a general reference. Actual sizing may vary slightly between brands and manufacturers. Hong Kong and Taiwan sizes in particular differ by retailer, so please treat these as approximate. Sizes 0 and -1 (used for petite/pinky rings) fall outside standard international conversion charts, so only the diameter/circumference in mm is shown for those rows. For the most accurate fit, please measure the inner diameter of a well-fitting ring, or the circumference of your finger (in mm), and compare it against the table above.
If you have any questions, please contact us at info@440showroom.tokyo.