Ring Size Conversion (US/UK/EU/JP)
Best practice: measure your inside ring diameter or finger circumference, then look up across.
| US | UK | EU mm | JP | Inside Ø mm |
|---|---|---|---|---|
| 3 | F | 44.0 | 4 | 14.0 |
| 3.5 | G | 45.5 | 6 | 14.5 |
| 4 | H | 47.0 | 7 | 14.8 |
| 4.5 | I | 48.0 | 8 | 15.3 |
| 5 | J½ | 49.5 | 9 | 15.7 |
| 5.5 | K½ | 50.7 | 10 | 16.1 |
| 6 | L½ | 51.9 | 11 | 16.5 |
| 6.5 | M½ | 53.0 | 13 | 16.9 |
| 7 | N½ | 54.4 | 14 | 17.3 |
| 7.5 | O½ | 55.7 | 15 | 17.7 |
| 8 | P½ | 57.0 | 16 | 18.1 |
| 8.5 | Q½ | 58.3 | 17 | 18.5 |
| 9 | R½ | 59.5 | 18 | 19.0 |
| 9.5 | S½ | 60.8 | 19 | 19.4 |
| 10 | T½ | 62.0 | 20 | 19.8 |
| 10.5 | U½ | 63.4 | 22 | 20.2 |
| 11 | V½ | 64.6 | 23 | 20.6 |
| 11.5 | W½ | 65.9 | 24 | 21.0 |
| 12 | Y | 67.2 | 25 | 21.4 |
| 13 | Z+1 | 69.5 | 27 | 22.2 |
About this tool
Ring Size Conversion (US/UK/EU/JP) is a single-purpose utility on instant.tw, a free toolbox of calculators, converters, generators, and quick lookups. Everything works in your browser — nothing is uploaded, nothing is stored on a server unless explicitly noted.
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