Ring Size Converter → US to UK Ring Size Converter
US to UK Ring Size Converter
Pick your US size to see the UK/Australia letter equivalent — plus Europe, Japan, and the exact millimeters. Switch the standard to convert the other way.
Enter a measurement above to see your size in every standard.
US to UK Ring Size chart
| US / CA | UK / AU | Europe | Circumference (mm) |
|---|---|---|---|
| 3 | F | 44 | 44.2 |
| 3.5 | G | 45½ | 45.5 |
| 4 | H½ | 47 | 46.8 |
| 4.5 | I½ | 48 | 48.0 |
| 5 | J½ | 49 | 49.3 |
| 5.5 | K½ | 50½ | 50.6 |
| 6 | L½ | 52 | 51.9 |
| 6.5 | M½ | 53 | 53.1 |
| 7 | N½ | 54 | 54.4 |
| 7.5 | O½ | 55½ | 55.7 |
| 8 | P½ | 57 | 57.0 |
| 8.5 | Q½ | 58 | 58.3 |
| 9 | R½ | 59½ | 59.5 |
| 9.5 | S½ | 61 | 60.8 |
| 10 | T½ | 62 | 62.1 |
| 10.5 | U½ | 63½ | 63.5 |
| 11 | V½ | 65 | 64.6 |
| 11.5 | W½ | 66 | 65.9 |
| 12 | Y | 67½ | 67.2 |
| 12.5 | Z | 68½ | 68.4 |
| 13 | Z+1 | 70 | 69.7 |
Industry-standard approximations; manufacturers vary slightly. If you're between sizes, round up.
FAQ
What is a US size 7 in UK ring sizes?
A US size 7 is approximately a UK/Australia size N½ (Europe 54, inside circumference 54.4 mm).
Why are UK ring sizes letters?
The UK and much of the Commonwealth use an alphabetical scale (A, B, C…) where each half-letter is roughly one third of a US size apart. The US uses a numeric scale, so the two never line up on whole numbers — hence the many half-sizes.
Are US and Canada ring sizes the same?
Yes. The US and Canada use the same numeric ring-size scale, so no conversion is needed between them.