Buying a ring for someone else, or for yourself online, and not sure of the size? Here is the method that works with a strip of paper and a ruler — plus the trick that gets you the size of someone else's finger without asking.
First: do you even need a size?
Most of our rings are open and adjustable, fitting roughly UK K to T. If the product page says Adjustable, there is nothing to measure. Skip to the bottom.
A smaller number of designs are made in fixed sizes. Those are the ones this guide is for.
Method 1: the paper strip (2 minutes)
- Cut a strip of paper about 5mm wide and 100mm long.
- Wrap it snugly around the base of the finger — snug, not tight. It needs to slide over the knuckle.
- Mark where the paper overlaps with a pen.
- Lay it flat and measure from the end to your mark, in millimetres.
That measurement is your finger circumference. Then read it off:
| Circumference | UK size | US size | Inside diameter |
|---|---|---|---|
| 49mm | J | 5 | 15.7mm |
| 52mm | L | 6 | 16.5mm |
| 54mm | N | 7 | 17.3mm |
| 57mm | P | 8 | 18.2mm |
| 60mm | R | 9 | 19.0mm |
Method 2: measure a ring they already own
This is the one for buying a surprise gift. Borrow a ring they wear on the right finger, stand it on a ruler and measure straight across the inside, edge to edge, in millimetres. That is the inside diameter — read it off the table above.
Be careful to borrow a ring from the same finger on the same hand. Most people are half a size to a full size different between hands.
Four things that catch people out
- Time of day. Fingers are largest in the late afternoon and in warm weather. Measure at the end of the day for the truest fit.
- Cold hands. Measuring straight after being outside in winter can put you a full size under.
- Band width. A wide band needs roughly half a size more than a fine one to feel the same.
- Knuckles. If the knuckle is noticeably larger than the base of the finger, size to slide over the knuckle, not to the base — or the ring will not go on.
If you are between sizes
Go down rather than up. A ring that is slightly tight can usually be sized up by a jeweller; one that spins and slips off gets lost.
Argenne fixed sizes
We stock three fixed sizes — L, N and P — cut to US whole sizes, so each sits around half a UK size above the letter shown. N is by far the most common.
If you are unsure, choose an adjustable design. They are the majority of our range for exactly this reason, and you can always ask us to hold a piece against a hand on the live show so you can judge the scale.