EU to UK ring size converter
Because an EU size is just the inner circumference in millimetres, converting to a UK letter is a matter of stepping through the alphabet at 1.25 mm per letter from the 40 mm anchor at size C. An EU 52 is roughly a UK L½; an EU 54 is roughly a UK N. Convert below.
Quick answer
A EU 54 is N½ in UK (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.
EU → UK at a glance
- 47 = H½
- 49 = J½
- 52 = L½
- 54 = N½
- 57 = P½
- 59 = R½
- 62 = T½
- 65 = V½
EU to UK ring size chart
| EUEU / ISO | UKUK / AU | mmCircumference | mmDiameter |
|---|---|---|---|
| 47 | H½ | 46.7 | 14.9 |
| 48 | I½ | 48.0 | 15.3 |
| 49 | J½ | 49.3 | 15.7 |
| 51 | K½ | 50.5 | 16.1 |
| 52 | L½ | 51.8 | 16.5 |
| 53 | M½ | 53.1 | 16.9 |
| 54 | N½ | 54.4 | 17.3 |
| 56 | O½ | 55.6 | 17.7 |
| 57 | P½ | 56.9 | 18.1 |
| 58 | Q½ | 58.2 | 18.5 |
| 59 | R½ | 59.5 | 18.9 |
| 61 | S½ | 60.7 | 19.3 |
| 62 | T½ | 62.0 | 19.7 |
| 63 | U½ | 63.3 | 20.1 |
| 65 | V½ | 64.6 | 20.5 |
| 66 | W½ | 65.8 | 21.0 |
| 67 | X½ | 67.1 | 21.4 |
Turning a millimetre figure into a letter
Your European size is already a measurement, so the only question is which letter sits closest to it. Start at size C, which is 40 mm, and count up in 1.25 mm steps. An EU 50 lands at about a UK K, an EU 52 at about L½, and an EU 54 at about N.
The converter above does the counting and includes half letters, which is where most European sizes actually land.
Half letters are not optional here
Because European sizes step in 1 mm and letters step in 1.25 mm, a European number usually falls between two whole letters rather than on one. Any chart that gives you only whole letters is rounding away up to 0.6 mm without telling you.
That is a small distance in isolation, but it is the difference between a ring that clears your knuckle and one that does not. If your result includes a half, treat the half as part of the size rather than a detail to drop when you order.
If you are buying in Britain or Ireland
High street jewellers in the UK and Ireland will size you with a set of steel rings or a mandrel and give you a letter. If you arrive already knowing your European size, bring the millimetre figure too, since that is the number they can check directly against their gauge.
It is worth being measured in person for an engagement ring or anything that cannot be resized later. Eternity rings with stones all the way round, and bands in tungsten or ceramic, generally cannot be altered afterwards.
Common questions
How do I convert a EU ring size to UK?
Enter your EU size in the converter above and read the UK 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 EU 54 in UK?
A EU 54 is N½ in UK. That ring has an inner circumference of about 54.4 mm.
Related conversions
Or see the full ring size chart.