UK to EU ring size converter
UK letters and EU numbers both trace back to the ring’s inner circumference, which makes conversion reliable. Each UK letter step is about 1.25 mm, and the EU number equals that circumference in mm. A UK L is around EU 51; a UK N is around EU 54. Convert below.
Quick answer
A UK N½ is 54 in EU (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 → EU at a glance
- H½ = 47
- J½ = 49
- L½ = 52
- N½ = 54
- P½ = 57
- R½ = 59
- T½ = 62
- V½ = 65
UK to EU ring size chart
| UKUK / AU | EUEU / ISO | mmCircumference | mmDiameter |
|---|---|---|---|
| H½ | 47 | 46.7 | 14.9 |
| I½ | 48 | 48.0 | 15.3 |
| J½ | 49 | 49.3 | 15.7 |
| K½ | 51 | 50.5 | 16.1 |
| L½ | 52 | 51.8 | 16.5 |
| M½ | 53 | 53.1 | 16.9 |
| N½ | 54 | 54.4 | 17.3 |
| O½ | 56 | 55.6 | 17.7 |
| P½ | 57 | 56.9 | 18.1 |
| Q½ | 58 | 58.2 | 18.5 |
| R½ | 59 | 59.5 | 18.9 |
| S½ | 61 | 60.7 | 19.3 |
| T½ | 62 | 62.0 | 19.7 |
| U½ | 63 | 63.3 | 20.1 |
| V½ | 65 | 64.6 | 20.5 |
| W½ | 66 | 65.8 | 21.0 |
| X½ | 67 | 67.1 | 21.4 |
Common questions
How do I convert a UK ring size to EU?
Enter your UK size in the converter above and read the EU 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 EU?
A UK N½ is 54 in EU. That ring has an inner circumference of about 54.4 mm.
Related conversions
Or see the full ring size chart.