UK to US ring size converter
To convert a UK ring size to US, you translate a letter (A to Z) into a number. UK sizes rise by roughly 1.25 mm of inner circumference per letter, so a UK L is about a US 6 and a UK N½ is a US 7. Pick your UK letter below to see the exact US equivalent.
Quick answer
A UK N½ is 7 in US (about 54.4 mm inner circumference). Use the converter for your exact size, or the chart below for the full range.
Between two sizes? Size up for a comfortable fit, see how to measure accurately.
UK → US at a glance
- H½ = 4
- J½ = 5
- L½ = 6
- N½ = 7
- P½ = 8
- R½ = 9
- T½ = 10
- V½ = 11
UK to US ring size chart
| UKUK / AU | USUS / Canada | mmCircumference | mmDiameter |
|---|---|---|---|
| H½ | 4 | 46.7 | 14.9 |
| I½ | 4½ | 48.0 | 15.3 |
| J½ | 5 | 49.3 | 15.7 |
| K½ | 5½ | 50.5 | 16.1 |
| L½ | 6 | 51.8 | 16.5 |
| M½ | 6½ | 53.1 | 16.9 |
| N½ | 7 | 54.4 | 17.3 |
| O½ | 7½ | 55.6 | 17.7 |
| P½ | 8 | 56.9 | 18.1 |
| Q½ | 8½ | 58.2 | 18.5 |
| R½ | 9 | 59.5 | 18.9 |
| S½ | 9½ | 60.7 | 19.3 |
| T½ | 10 | 62.0 | 19.7 |
| U½ | 10½ | 63.3 | 20.1 |
| V½ | 11 | 64.6 | 20.5 |
| W½ | 11½ | 65.8 | 21.0 |
| X½ | 12 | 67.1 | 21.4 |
Common questions
How do I convert a UK ring size to US?
Enter your UK size in the converter above and read the US result, or find your row in the chart below. Every value is calculated from the ring’s inner circumference, so it works in both directions.
What is a UK N½ in US?
A UK N½ is 7 in US. That ring has an inner circumference of about 54.4 mm.
Related conversions
Or see the full ring size chart.