A ring that fits is one you stop noticing. Too tight, and it is the first thing you take off at the end of the day. Too loose, and it spins round on the finger, or slips off when your hands are cold. For an engagement ring, a wedding band or any ring you mean to wear every day, a few minutes spent on the size is worth it.
The surest way to find your ring size is to have a jeweller measure your finger. At home, you can measure the inside of a ring that already fits, or wrap a thin strip of string round your finger, and match the result to the chart below. UK sizes are letters, and each step is just over a millimetre of circumference.
At Anupam, we can measure your finger in the shop in Ashford, and we resize rings in our own workshop if one you already own has stopped fitting. If you are still choosing the ring itself, our guide to how to find the right ring covers style, stone and setting.
What are UK ring sizes, and how do they convert to US sizes?
UK ring sizes run through the alphabet, and the chart below covers H to Z. Sizes also come in halves, such as L½, which sit halfway between two letters. Circumference is the distance round the inside of the ring; diameter is the distance straight across it.
| UK size | Circumference (mm) | Diameter (mm) | Approx. US size |
|---|---|---|---|
| H | 46.8 | 14.9 | 4 |
| I | 48.0 | 15.3 | 4.5 |
| J | 49.3 | 15.7 | 5 |
| K | 50.6 | 16.1 | 5.5 |
| L | 51.9 | 16.5 | 6 |
| M | 53.1 | 16.9 | 6.5 |
| N | 54.4 | 17.3 | 7 |
| O | 55.7 | 17.7 | 7.5 |
| P | 57.0 | 18.1 | 8 |
| Q | 58.3 | 18.5 | 8.5 |
| R | 59.5 | 19.0 | 9 |
| S | 60.8 | 19.4 | 9.5 |
| T | 62.1 | 19.8 | 10 |
| U | 63.4 | 20.2 | 10.5 |
| V | 64.6 | 20.6 | 11 |
| W | 65.9 | 21.0 | 11.5 |
| X | 67.2 | 21.4 | 12 |
| Y | 68.5 | 21.8 | 12.5 |
| Z | 69.7 | 22.2 | 13 |
The right-hand column gives the nearest US size. The two systems are measured differently, so treat any conversion as a guide rather than an exact match. If you are buying from a US website, check the millimetre measurements as well.
How do I measure my ring size at home?
There are three ways to do it. The first two use the chart above; a ring sizer gives you the size directly.
Measure a ring that already fits
Choose a ring that fits the finger you are sizing, one that feels neither tight nor loose. With a ruler, measure straight across the inside, from one inner edge to the other at the widest point, not including the metal. Match the result to the Diameter column.
Measure your finger with string
- Cut a thin strip of string or dental floss, something that won’t stretch.
- Wrap it once round the base of the finger and mark where it meets.
- Lay it flat against a ruler and read the length in millimetres.
- Match that to the Circumference column.
A strip of paper works too, but cut it narrow so it doesn’t bunch.
An example: a strip that measures 54.4mm matches a UK N.
Use a ring sizer
A ring sizer is a set of sample rings in different sizes, the same tool a jeweller uses, and it is the most reliable way to check at home. If you print a ring size chart from a website instead, hold a ruler against the printout first to make sure it printed at the right scale.
Which method is most accurate?
| Method | Reliability | Why |
|---|---|---|
| Measured by a jeweller | The most reliable | They can feel how a ring sits over your knuckle |
| Ring sizer at home | Next best | Sample rings, like the ones a jeweller uses |
| A ring that already fits | Good | As long as it is worn on the same finger of the same hand |
| String or paper | Fair | The result depends on how snugly you pull it |
| Printed or on-screen sizer | The least reliable | Printers and screens can change the scale |
For a ring you are about to buy, it is worth checking a home measurement with a second method, or having your finger measured in person.
Can I measure my ring size on my phone?
Not reliably. Phone screens differ in size, and zoom settings change what appears on them, so an on-screen sizer can be well out. It is fine for a rough idea, but use the chart above or have a jeweller measure you for anything you are going to buy. Our ring size guide page has more.
When is the best time to measure?
- At the end of the day, when your fingers are warm. Fingers are smaller when cold and larger when warm or after exercise.
- More than once. Measure on two or three different days and take the middle result.
- With your knuckle in mind. If your knuckle is wider than the base of your finger, choose the size that slides over it with a little resistance and still stays put once it is on.
Measure the hand you will wear the ring on, as your dominant hand is often a little larger than the other. The same goes for the finger: a signet ring on the little finger takes a smaller size than one on the ring finger, as our post on signet rings explains.
Can my ring size change?
Yes. Fingers change with temperature, weight, pregnancy and the passing years, and knuckles can widen. It is very common for a ring worn for years to stop fitting, and it is often straightforward to put right.
Our post on ring resizing explains how it is done and which rings can and can’t be altered.
Do wide bands and stacks need a bigger size?
Often, yes. A wide band covers more of the finger, so it feels tighter than a narrow one of the same size, and from about 6mm many people go up half a size. Two or three rings worn together feel snugger too.
Our wedding ring builder offers widths from 2mm to 8mm. If you are considering one of the wider bands, have your size checked against a band of a similar width before you order. How to choose a wedding band covers width and profile, and our post on which finger, and in what order covers wearing rings together.
Can I change the size afterwards?
Most rings can be made larger or smaller at the bench. The exceptions are worth knowing before you buy.
| Ring | Can it be resized? |
|---|---|
| Plain band, or a stone on a plain band | Usually, yes |
| Half eternity ring | Usually a little, depending on how far round the stones go |
| Full eternity ring | Generally not, because there is no plain metal to cut |
| Patterned band | Can be difficult, because a join would interrupt the pattern |
So with an eternity ring in particular, get the size right first. Our post on eternity rings explains the difference between half and full, and it is worth trying our eternity rings on for size before you decide.
How do I find out someone’s ring size without them knowing?
- Borrow a ring they already wear on the finger the new ring will go on, and measure the inside as above. If you can’t take it away for long, press it onto a sheet of paper and trace round the inside.
- Ask someone close to them. A sister, a parent or a best friend may well know, and can keep a secret.
- If you can only guess, err slightly larger. A ring that is a touch loose can still be worn on the day, but one that is too small can’t, and most engagement rings can be resized afterwards.
Have your finger measured in Ashford
If you would like to be sure, book a time with us in Ashford. We will measure your finger, go through width and style with you, and you can try rings on at the same time. You can browse by style first in our ring collection.
Frequently asked questions
What if my measurement falls between two sizes?
You may be a half size, such as L½; if the ring is a wide band, or will be worn with others, the larger of the two is usually the better choice.
How should a ring feel when it fits?
It should slide over the knuckle with a little resistance and stay put once it is on, without leaving a deep mark. If it spins so that the stone turns towards your palm, it is probably too big.
Is my ring size the same on every finger?
No. Each finger is a different size, and the same finger can differ from one hand to the other.
What is a US size 7 in UK sizes?
A US 7 is approximately a UK N, with an inside circumference of 54.4mm.
Should I bring my other rings when I’m measured?
Yes, if the new ring will be worn beside them.
