UK Ring Size Chart
Every UK size from A to Z in mm, with US and EU conversions and how to measure.
Read guide 6 min read
Free ring sizer
What's your ring size?
Match a ring on your screen, measure your finger with a strip of paper, or print a free sizer. You get your UK size, plus US and EU, in about two minutes.
Step 1: Match a bank card
Every screen is a different size, so we need to calibrate once. Hold any bank card upright and flat against the screen, and resize the box until it’s exactly as wide as the card’s short edge.
No card to hand? Use the printable sizer, or measure your finger with string instead.
Prefer paper? Print a free ring sizer or see the full UK ring size chart.
Planning a surprise?
Finding someone else's ring size without asking
Borrow a ring they already wear, measure it in secret, or ask someone who knows.
Borrow one of her rings
The most reliable way to get an accurate size — no measurements needed.
Which ring to borrow
- 1Right ring finger is your best bet. It's typically the closest in size to the left ring finger — often identical or within half a size.
- 2Avoid index or middle finger rings — these are usually 1-2 sizes larger than the ring finger.
- 3Pinky rings are too small. Don't use those either.
What to do with the ring
- Take it to any Hatton Garden jeweller — they'll measure it for free in 30 seconds using a ring mandrel
- If you can't take it in, press the ring into a bar of soap to leave an imprint, then measure the inner diameter with a ruler and check the chart below
- Return it before she notices — borrow it when she's in the shower, at the gym, or out with friends
Pro tip: If she only wears rings on her middle or index finger, try one on your own hand and note which of your fingers it fits. Then get that finger sized at a jeweller — it gives you a reference point.
UK Ring Size Chart
Match your measurement to the chart below. If you fall between two sizes, go up — a slightly loose ring is easier to resize than one that won't fit over the knuckle.
| UK Size | US Size | Diameter(mm) | Circumference(mm) |
|---|---|---|---|
| H | 3¾ | 14.8 | 46.4 |
| I | 4¼ | 15.2 | 47.6 |
| J | 4¾ | 15.6 | 48.9 |
| K | 5¼ | 15.9 | 50.1 |
| LMost common | 5¾ | 16.3 | 51.3 |
| MMost common | 6¼ | 16.7 | 52.5 |
| NMost common | 6¾ | 17.1 | 53.8 |
| O | 7¼ | 17.5 | 55.0 |
| P | 7¾ | 17.9 | 56.2 |
| Q | 8¼ | 18.3 | 57.4 |
| R | 8¾ | 18.7 | 58.7 |
| S | 9¼ | 19.1 | 59.9 |
| T | 9¾ | 19.5 | 61.1 |
UK jewellers report most women's ring sizes fall between L and N, with M the most common. Men's usually fall between R and T.
If you get it wrong — it's not the end of the world
Most Hatton Garden jewellers will resize a ring within 1-2 sizes for free, provided you come back within 30 days. Some styles (full eternity bands, tension settings) are harder to resize, so check with your jeweller at the time of purchase.
- Solitaires, halos, and most classic settings resize easily
- Going up is easier than going down — order slightly smaller if unsure
- Ask for a free resize guarantee before you buy — most reputable jewellers offer one
Now you know her size — ready to design the ring?
Try the Ring BuilderCommon Questions
How do I measure my ring size at home?+
Three ways: match a ring that already fits against the circle on this page (after a quick bank-card calibration), wrap a strip of paper around your finger and measure it in millimetres, or print our free ring sizer. All three are accurate to about half a size.
What is the most common ring size in the UK?+
UK jewellers report most women’s ring sizes fall between L and N, with M the most common (US 6¼). Men’s usually fall between R and T. If you have to guess, it’s easier to resize a ring down than up.
Can an engagement ring be resized if I get the size wrong?+
Yes. Most Hatton Garden jewellers will resize a ring within 1-2 sizes for free, typically within 30 days of purchase. Simple styles like solitaires and halos resize easily. Full eternity bands and tension-set rings are harder to resize, so getting the size right first time matters more with those designs. Always ask about the resize policy before you buy.
Is my left ring finger the same size as my right?+
They're usually very close — often identical or within half a UK size. Your dominant hand is sometimes marginally larger. If you can only borrow a ring from her right ring finger, it's still a reliable guide. The difference is small enough that a free resize can handle it.
Do fingers change size throughout the day?+
Yes. Fingers swell slightly during the day due to activity and warmth, and shrink in cold weather or first thing in the morning. For the most accurate measurement, measure at the end of the day at room temperature. If you're between two sizes, go with the larger one.
How accurate is the string method for ring sizing?+
The string or paper method is accurate to within about half a UK size when done carefully. The key is wrapping it firmly but not tightly, marking the overlap point precisely, and measuring in millimetres against a ruler. For a perfect fit, take your measurement to a jeweller and they'll confirm it with a professional gauge — most do this for free.
Useful next steps
How to Choose an Engagement Ring
Shape, metal, setting, budget — the decisions you need to make before you walk into a shop.
Read guide 10 min read
Hatton Garden Price Guide
What engagement rings actually cost in Hatton Garden. Real price ranges, not vague estimates.
Read guide 8 min read
Visiting Hatton Garden
First-timer's guide to London's diamond quarter. How to get there, what to expect, and how to prepare.
Read guide 7 min read