European (EU) ring sizes use circumference in millimeters, and UK ring sizes use alphabet letters. Converting between them is a common need when buying from a brand that lists EU sizing, like Cartier or Pandora, while you know your ring size in UK letters.
This guide gives you a direct EU to UK conversion chart, explains why the numbers do not match 1:1, and shows you how to get the most reliable result when sizing falls between two letters.
EU to UK Ring Size Conversion Chart
| EU size | UK size | US size | Inner diameter (mm) |
|---|---|---|---|
| 44 | F | 3 | 14.1 |
| 45.5 | G | 3.5 | 14.5 |
| 46.8 | H | 4 | 14.9 |
| 48 | I½ | 4.5 | 15.3 |
| 49.3 | J½ | 5 | 15.7 |
| 50.6 | K½ | 5.5 | 16.1 |
| 51.9 | L½ | 6 | 16.5 |
| 53.1 | M½ | 6.5 | 16.9 |
| 54.4 | N½ | 7 | 17.3 |
| 55.7 | O½ | 7.5 | 17.7 |
| 57.2 | P½ | 8 | 18.2 |
| 58.5 | Q½ | 8.5 | 18.6 |
| 59.7 | R½ | 9 | 19.0 |
| 61 | S½ | 9.5 | 19.4 |
| 62.2 | T½ | 10 | 19.8 |
| 63.5 | U½ | 10.5 | 20.2 |
| 64.8 | V½ | 11 | 20.6 |
| 67.2 | X½ | 12 | 21.4 |
| 69.7 | Z | 13 | 22.2 |
Why EU and UK Sizes Do Not Match Directly
The EU system represents the inner circumference of the ring in millimeters. The UK system uses letters, where each full letter step is roughly 1.25mm in circumference. Because one system counts millimeters and the other counts letter steps, there is no fixed formula that works cleanly across the full range without a reference table.
Half-letters like J½ and N½ exist in the UK system to provide finer resolution. Many UK jewelers stock both full and half-letter sizes, but some cheaper retailers only carry full letters. When a half-letter size converts from EU and the retailer only stocks full letters, going up one letter is usually the safer choice.
Common EU to UK Conversions
EU 52 to UK: the closest match is L½ (US 6). EU 54 to UK: N½ (US 7). EU 57 to UK: P½ (US 8). EU 60 to UK: R½ to S (US 9). These cover a large range of typical jewellery sizing in the UK market.
For Cartier specifically, the EU size on the tag can be used directly with this chart. See our Cartier ring size guide for the full brand-specific table. For US-based brands with EU sizing listed, see our US to EU ring size conversion guide.
How to Get Your Own EU Size
Measure your finger circumference in millimeters using a paper strip and ruler. That circumference value is your EU size. Then find it in the left column of the chart above and read across to the UK letter.
For the most accurate home measurement, use our calibrated ring size calculator on your phone. It gives you your size in all systems at once, so you do not need to convert manually. For a full walkthrough of home measurement methods, see how to measure ring size at home.
FAQ
What is EU 54 in UK ring size?
EU 54 is approximately UK N½, US 7, with an inner diameter of about 17.3mm.
What is EU 52 in UK size?
EU 52 is close to UK L½, which is US 6, with an inner diameter of about 16.5mm.
What does the EU ring size number mean?
The EU ring size number represents the inner circumference of the ring in millimeters. EU 52 means the ring has an inner circumference of approximately 52mm.
Is European ring sizing the same as French sizing?
Yes. French, German, Italian, and most other European countries use the same circumference-based EU system.
