Getting the ring size right is the one detail that can make or break a perfect moment. This guide gives you the full UK ring size chart, explains how the letter system works, and shows three simple ways to measure at home.
How UK ring sizes work
In the UK, ring sizes are given as letters, from A (smallest) to Z (largest), with half sizes in between (for example, M½). Each full letter is roughly 1.25mm larger in circumference than the one before it.
Two measurements matter:
- Inside circumference – the distance around the inside of the ring.
- Inside diameter – the distance straight across the inside of the ring.
UK ring size chart
| UK size | Inside circumference (mm) | Inside diameter (mm) |
|---|---|---|
| H | 46.8 | 14.9 |
| I | 48.0 | 15.3 |
| J | 49.3 | 15.7 |
| K | 50.6 | 16.1 |
| L | 51.8 | 16.5 |
| M | 53.1 | 16.9 |
| N | 54.4 | 17.3 |
| O | 55.7 | 17.7 |
| P | 57.0 | 18.1 |
| Q | 58.3 | 18.6 |
| R | 59.5 | 18.9 |
| S | 60.8 | 19.4 |
| T | 62.1 | 19.8 |
| U | 63.4 | 20.2 |
| V | 64.6 | 20.6 |
| W | 65.9 | 21.0 |
| X | 67.2 | 21.4 |
| Y | 68.5 | 21.8 |
| Z | 69.7 | 22.2 |
Measurements are rounded to one decimal place. Charts from different jewellers can vary slightly, so if you are between two sizes, choose the larger one.
Three ways to find your ring size at home
1. Measure a ring you already own (most accurate)
Take a ring that fits the right finger comfortably. Lay it on a ruler and measure straight across the inside edge, in millimetres. Match that number to the inside diameter column above.
2. The string or paper method
- Wrap a thin strip of paper or non-stretchy string around the base of your finger.
- Mark where the ends meet with a pen.
- Lay it flat on a ruler and measure the length in millimetres.
- Match that number to the inside circumference column above.
Make sure it is snug but can still slide over your knuckle. String stretches easily, so paper usually gives a better result.
3. Ask a jeweller
Any high-street jeweller can size your finger in a minute, usually free of charge. This is the best option if you are unsure.
Tips for an accurate measurement
- Measure at the end of the day. Fingers are slightly larger in the evening.
- Avoid cold days. Fingers shrink in the cold, which can make a ring too tight later.
- Measure the right hand. Your dominant hand is often slightly larger.
- Think about the knuckle. If your knuckle is larger than the base of your finger, the ring must fit over it.
- Wide bands fit tighter. For a band wider than about 6mm, consider going up half a size.
Finding their ring size secretly for a proposal
- Borrow a ring they wear on the ring finger, measure it, and put it back quickly.
- Press it into soap or trace the inside of the ring on paper if you can't take it away.
- Ask a close friend or family member who may already know.
- If in doubt, size up. A slightly large ring is easier to adjust than a small one.
Ready to choose?
Every piece we make is crafted to order in your UK ring size. Browse our engagement rings, wedding rings or all rings. If you have any questions about sizing, message us on WhatsApp and we'll help you get it right.
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