Ring size converter
Convert US, UK, EU, and JP ring sizes with diameter and circumference.
Convert a ring size
Choose the size system you have. The closest equivalent updates across every system.
US
3
UK
F
EU
44
JP
4
US 3 is approximately 14.1 mm diameter and 44.3 mm circumference.
Conversion is a reference, not a fitting
Ring profiles and manufacturer tolerances vary. Confirm valuable purchases with the seller.
Measure first| US | UK | EU | JP | Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|---|
| 3 | F | 44 | 4 | 14.1 | 44.3 |
| 3.5 | G | 46 | 6 | 14.5 | 45.6 |
| 4 | H | 47 | 7 | 14.9 | 46.8 |
| 4.5 | I | 48 | 8 | 15.3 | 48.1 |
| 5 | J | 49 | 9 | 15.7 | 49.3 |
| 5.5 | K | 51 | 10 | 16.1 | 50.6 |
| 6 | L | 52 | 12 | 16.5 | 51.8 |
| 6.5 | M | 53 | 13 | 16.9 | 53.1 |
| 7 | N | 54 | 14 | 17.3 | 54.3 |
| 7.5 | O | 56 | 15 | 17.7 | 55.6 |
| 8 | P | 57 | 16 | 18.1 | 56.9 |
| 8.5 | Q | 58 | 18 | 18.5 | 58.1 |
| 9 | R | 60 | 19 | 19.0 | 59.7 |
| 9.5 | S | 61 | 20 | 19.4 | 60.9 |
| 10 | T | 62 | 21 | 19.8 | 62.2 |
| 10.5 | U | 64 | 23 | 20.2 | 63.5 |
| 11 | V | 65 | 24 | 20.6 | 64.7 |
| 11.5 | W | 66 | 25 | 21.0 | 66.0 |
| 12 | X | 67 | 26 | 21.4 | 67.2 |
| 12.5 | Y | 69 | 27 | 21.8 | 68.5 |
| 13 | Z 1/2 | 70 | 29 | 22.2 | 69.7 |