Ring size conversion
UK ring size R in US and European sizes
UK ring size R is US size 8.75 and European (ISO) size 59.1. The inside diameter is 18.8 mm and the circumference 59.06 mm.
Checking it yourself
Measure straight across the inside of a ring that already fits. About 18.8 mm means UK R. Or wrap paper around the finger and measure the length — about 59.06 mm is the same size.
The UK, Ireland and Australia share this letter system, sometimes called the Wheat Sheaf scale. The US uses numbers, and Europe uses the circumference in millimetres directly, which is why the European size and the circumference above are the same figure.
Full conversion chart
| UK / AU | US | Europe | India / Japan | Diameter |
|---|---|---|---|---|
| F | 3 | 44.1 | 4 | 14.05 mm |
| F½ | 3.25 | 44.8 | — | 14.25 mm |
| G | 3.5 | 45.4 | 5 | 14.45 mm |
| G½ | 3.75 | 46 | — | 14.65 mm |
| H | 4 | 46.7 | 6 | 14.86 mm |
| H½ | 4.25 | 47.3 | — | 15.06 mm |
| I | 4.5 | 48 | 7 | 15.27 mm |
| J | 4.75 | 48.6 | 8 | 15.47 mm |
| J½ | 5 | 49.3 | 9 | 15.7 mm |
| K | 5.25 | 50 | — | 15.9 mm |
| K½ | 5.5 | 50.6 | 10 | 16.1 mm |
| L | 5.75 | 51.2 | — | 16.3 mm |
| L½ | 6 | 51.9 | 11 | 16.51 mm |
| M | 6.25 | 52.5 | — | 16.71 mm |
| M½ | 6.5 | 53.2 | 12 | 16.92 mm |
| N | 6.75 | 53.8 | 13 | 17.13 mm |
| N½ | 7 | 54.5 | 14 | 17.35 mm |
| O | 7.25 | 55.1 | — | 17.55 mm |
| O½ | 7.5 | 55.8 | 15 | 17.75 mm |
| P | 7.75 | 56.5 | — | 17.97 mm |
| P½ | 8 | 57.1 | 16 | 18.19 mm |
| Q | 8.25 | 57.8 | — | 18.39 mm |
| Q½ | 8.5 | 58.2 | 17 | 18.53 mm |
| R | 8.75 | 59.1 | — | 18.8 mm |
| R½ | 9 | 59.5 | 18 | 18.95 mm |
| S | 9.25 | 60.4 | — | 19.22 mm |
| S½ | 9.5 | 61 | 19 | 19.41 mm |
| T | 9.75 | 61.6 | — | 19.62 mm |
| T½ | 10 | 62.3 | 20 | 19.84 mm |
| U | 10.25 | 62.9 | — | 20.02 mm |
| U½ | 10.5 | 63.5 | 22 | 20.2 mm |
| V | 10.75 | 64.2 | — | 20.44 mm |
| V½ | 11 | 65 | 23 | 20.68 mm |
| W½ | 11.5 | 66.2 | 24 | 21.08 mm |
| X½ | 12 | 67.5 | 25 | 21.49 mm |
| Y½ | 12.5 | 68.8 | 26 | 21.89 mm |
| Z½ | 13 | 70.2 | 27 | 22.33 mm |
Measure it on your screen
Lay a ring against circles drawn true to life, calibrated with any bank card.
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