Ring size conversion
UK ring size F in US and European sizes
UK ring size F is US size 3 and European (ISO) size 44.1. The inside diameter is 14.05 mm and the circumference 44.14 mm.
Checking it yourself
Measure straight across the inside of a ring that already fits. About 14.05 mm means UK F. Or wrap paper around the finger and measure the length — about 44.14 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
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