Reference
Ring size guide
We work to the UK letter scale. Every size below is listed with its inner circumference, which is the measurement that actually matters and the one the studio uses.
On a made-to-order piece the size is not only about fit: it changes the weight, and the weight decides whether your piece must be hallmarked.
Version 2026-08-12 · PRIVATE JEWELLER LIMITED · Governing law: England and Wales
The UK scale, H to Z
| UK size | Inner circumference | Inner diameter | Usable engraving width inside a band, after the 8 mm hallmark reserve |
|---|---|---|---|
| H | 46.8 mm | 14.9 mm | 38.8 mm |
| I | 48.0 mm | 15.3 mm | 40.0 mm |
| J | 48.7 mm | 15.5 mm | 40.7 mm |
| K | 50.0 mm | 15.9 mm | 42.0 mm |
| L | 51.2 mm | 16.3 mm | 43.2 mm |
| M (our reference size) | 52.5 mm | 16.7 mm | 44.5 mm |
| N | 53.8 mm | 17.1 mm | 45.8 mm |
| O | 55.1 mm | 17.5 mm | 47.1 mm |
| P | 56.3 mm | 17.9 mm | 48.3 mm |
| Q | 57.6 mm | 18.3 mm | 49.6 mm |
| R | 58.9 mm | 18.7 mm | 50.9 mm |
| S | 60.2 mm | 19.2 mm | 52.2 mm |
| T | 61.4 mm | 19.5 mm | 53.4 mm |
| U | 62.7 mm | 20.0 mm | 54.7 mm |
| V | 64.0 mm | 20.4 mm | 56.0 mm |
| W | 65.3 mm | 20.8 mm | 57.3 mm |
| X | 66.6 mm | 21.2 mm | 58.6 mm |
| Y | 67.9 mm | 21.6 mm | 59.9 mm |
| Z | 69.1 mm | 22.0 mm | 61.1 mm |
Half sizes exist between most letters. If you are between two, tell us in the notes at checkout and we will make the half size at no extra charge.
How to measure at home
The reliable method: measure a ring that fits
- Take a ring that fits the right finger.
- Measure the inside diameter across the widest point, in millimetres, with a ruler you trust.
- Multiply by 3.14 to get the circumference, and find it in the table above.
The less reliable method: measure the finger
- Wrap a strip of paper around the base of the finger. Not thread, which stretches, and not tape, which does not.
- Mark where it meets, take it off flat, and measure to the mark in millimetres.
- That is the circumference. Find it in the table.
Four things that will make you order the wrong size:
- Measuring when you are cold. Fingers can be a full size smaller.
- Measuring in the evening on a hot day. They can be a size larger.
- Forgetting the knuckle — the ring has to pass it. Check by sliding your test ring off.
- Measuring the wrong hand. The dominant hand is usually a little larger.
Measure twice, on two different days, at a normal temperature. If the two readings disagree, take the larger.
Band width changes the fit
A wide band feels tighter than a narrow one at the same nominal size, because it sits against more of the finger.
- Up to 4 mm wide: order your measured size.
- 5 to 6 mm: consider a half size up.
- 8 mm and above: a half to a full size up, and try a wide ring on before you commit if you can.
Our court profile bands are domed and rounded on the inside, which makes them noticeably kinder than a flat band of the same width. If you are between sizes on a flat 6 mm or the 8 mm wide band, go up.
Size, weight and hallmarking
This is the part that surprises people. A larger ring uses more metal, so it weighs more — and the hallmarking exemption is a weight, not a size. The same blank in the same metal can sit under the exemption at one size and over it at another, which changes both the price and the lead time.
The studio recalculates the estimated weight every time you change the size, and the docket says plainly whether the piece will be submitted for hallmarking. If you are near the line, you will see the row flash as you cross it. See hallmarking for what the submission involves.
A larger size also gives you more room inside the band. Size Z gives you 61.1 mm of usable width after the hallmark reserve; size H gives you 38.8 mm. On a long inscription that can be the difference between one line and two.
Bangles and cuffs
| Size | Inner circumference | Suits |
|---|---|---|
| Small — 180 mm | 180 mm | A slim wrist, or a snug fit |
| Medium — 190 mm | 190 mm | Most adult wrists |
| Large — 200 mm | 200 mm | A larger wrist, or a loose fit |
A solid bangle has to pass the hand, not the wrist. Squeeze your hand as small as it will go and measure around the widest part — across the knuckles and the base of the thumb. That measurement, plus a few millimetres, is the size you need. Our open cuff avoids the problem entirely and can be eased a little by hand.
If the size turns out to be wrong
Ordering the wrong size is not a fault, so the piece is not returnable once it has been engraved — see returns. But it is usually fixable, so write to us before you assume otherwise.
- Plain bands can normally be resized by one or two sizes for a workshop charge.
- An inscription inside the band may need to be re-cut after resizing, because stretching or cutting the shank moves the layout. We will tell you before we touch it.
- Hallmarked pieces can be resized, but the mark must not be damaged or removed. Sometimes that constrains where we can work.
- Spinner rings, lockets and hinged pieces cannot be resized. Measure carefully before ordering one.