Reference · United Kingdom, Australia & New Zealand
UK ring size chart
British ring sizes are letters, not numbers, and they run in half-letter steps: L, L½, M, M½. One letter is roughly half a US size, which is why a conversion that is one letter out is only a quarter of a US size out — and still enough to feel wrong on the finger. The table below gives every letter as an inside diameter in millimetres.
Instant converter
Already know a size?
- US / CA
- —
- UK / AU
- —
- EU / ISO
- —
- India
- —
- Japan
- —
- Circumference
- —
No calibration needed — this is pure conversion. Measure now
The table
UK ring sizes in mm
Whole letters only below — the half-letter steps sit exactly between two rows. Australia and New Zealand read the same scale, unchanged.
| UK / AU | Ø mm | Circ. mm | US / CA | EU / ISO | India | Japan |
|---|---|---|---|---|---|---|
| D | 13.3 | 41.6 | 2 | 42 | 2 | #2 |
| E | 13.7 | 42.9 | 2½ | 43 | 3 | #3 |
| F | 14.1 | 44.2 | 3 | 44 | 4 | #4 |
| G | 14.5 | 45.5 | 3½ | 45 | 5 | #5 |
| H | 14.9 | 46.8 | 4 | 47 | 7 | #6 |
| I | 15.3 | 48.0 | 4½ | 48 | 8 | #8 |
| J | 15.7 | 49.3 | 5 | 49 | 9 | #9 |
| K | 16.1 | 50.6 | 5½ | 51 | 11 | #10 |
| L | 16.5 | 51.9 | 6 | 52 | 12 | #11 |
| M | 16.9 | 53.1 | 6½ | 53 | 13 | #13 |
| N | 17.3 | 54.4 | 7 | 54 | 14 | #14 |
| O | 17.7 | 55.7 | 7½ | 56 | 15 | #15 |
| P | 18.1 | 57.0 | 8 | 57 | 17 | #16 |
| Q | 18.5 | 58.2 | 8½ | 58 | 18 | #17 |
| R | 18.9 | 59.5 | 9 | 60 | 19 | #18 |
| S | 19.4 | 60.8 | 9½ | 61 | 21 | #19 |
| T | 19.8 | 62.1 | 10 | 62 | 22 | #21 |
| U | 20.2 | 63.3 | 10½ | 63 | 23 | #22 |
| V | 20.6 | 64.6 | 11 | 65 | 25 | #23 |
| W | 21.0 | 65.9 | 11½ | 66 | 26 | #24 |
| X | 21.4 | 67.2 | 12 | 67 | 27 | #25 |
| Y | 21.8 | 68.5 | 12½ | 68 | 28 | #27 |
| Z | 22.2 | 69.7 | 13 | 70 | 30 | #28 |
Derived from ISO 8653. Manufacturing tolerance on a finished ring is typically ±0.1 mm, which is well inside one letter.
How the letter scale works
The British scale is alphabetic and roughly linear: each successive letter adds about 0.4 mm of inside diameter, and each half-letter about 0.2 mm. It runs from A at the very small end through Z, and then continues as Z+1, Z+2 and upward for the largest sizes, which is where the men’s range mostly sits.
Because the steps are finer than US half sizes, a UK letter carries slightly more precision than a US number. A UK N is a US 6¾, and a UK N½ is a US 7 — the two scales do not line up on whole steps, so converting between them almost always involves rounding. Round up rather than down.
One useful British quirk: hallmarked rings are frequently stamped with their size inside the band, alongside the assay marks. If you have inherited a ring, look inside it before measuring anything — it may already tell you its own size.
How a British jeweller measures your letter
In a UK shop the finger is sized with a set of ring gauges: a bunch of metal rings, one for every letter and half letter, slipped over the knuckle until one sits right. A ring you bring in is read on a ring stick, a tapered steel mandrel marked with the letters, by sliding it down until it stops.
The gauges are why a jeweller’s letter is hard to beat at home. They pass over the knuckle and sit at the base exactly as a ring will, and wide-band gauges exist for chunky rings. String and paper strips measure only the base of the finger and ignore the knuckle, which is why they can read small.
The home equivalent of the ring stick is measuring a ring that already fits: its inside diameter is fixed, and the table above turns it into a letter. The calibrated on-screen sizer does that reading to about ±0.15 mm, well inside one letter.
Converting a UK size to US, EU or Indian sizes
Read across the table, or use the converter above, which takes a diameter and gives every scale at once. The international ring size chart holds all five in one row if you are moving between markets repeatedly, and the US ring size chart goes deeper on the American scale and the formula behind it. Starting from a US number, US to UK ring size converts it letter by letter.
If the size you are starting from was itself a conversion — a UK letter someone worked out from a US number, say — do not convert it again. Each hop rounds, and two hops can move you a full size. Go back to a millimetre measurement instead.
Getting it right
Three things that move a British ring size
- Half letters are real sizes
- L½ and M½ are stocked as readily as L and M. If your measurement lands between two letters, the half step is usually available — ask before rounding.
- Wide bands need a letter more
- A band of 5 mm or more wears tighter at the same nominal size. Add about one letter from 5 mm of width, and two from 9 mm.
- Cold hands read small
- A British winter can move a finger by a full letter. Measure indoors, in the late afternoon, at room temperature.
The same scale elsewhere
Who else reads letters
Australia, New Zealand, Ireland and South Africa all use the British letter scale unchanged. Pick a country to see what a given diameter is called there.
Do not know it? Measure a ring on your calibrated screen — it is the only number here that is not a conversion of another number.
Indian numeric
14
A number from 1 to about 30. Indian jewellers frequently print the UK letter beside it, because both are in daily use.
India. Indian jewellers quote a numeric scale of their own, roughly 1 to 30. Tanishq, Malabar Gold, Kalyan and GIVA all use it, and many print the UK letter beside it. Online-first brands often list US sizes as well, so check which scale a listing means before ordering. Full India ring size chart.
United States. The US numeric scale, sold mostly in half sizes. Quarter sizes exist and a jeweller can cut them, but they are rarely stocked. Full USA ring size chart.
United Kingdom. Letters, in half-letter steps. British hallmarked rings are usually stamped with the letter, so an inherited ring often tells you its own size if you look inside the band. Full UK ring size chart.
Europe. France, Germany, the Netherlands and Scandinavia quote the ISO 8653 number, which is the inside circumference in millimetres. Italy, Spain and Switzerland quote the same measurement minus 40, so a 54 becomes a 14. Full Europe ring size chart.
Japan. The Japanese numeric scale runs #1 to about #27 for the sizes people actually order. Mikimoto, Tasaki and 4°C all use it. Japanese sizes are usually whole numbers only. Full Japan ring size chart.
China. Mainland Chinese listings usually give 圈号 — the inside circumference in millimetres, the same number as EU/ISO. Hong Kong uses a separate numbered scale, and marketplace listings mix both with US sizes. Order by inside diameter in millimetres when a listing does not say which scale it means.
Australia. Australia and New Zealand use the UK letter scale unchanged, so a UK N is an Australian N.
Canada. Identical to the United States. A US 7 is a Canadian 7, with no conversion in between.
Singapore. Singapore retail is mixed: international brands quote US numbers, goldsmiths in the Chinese tradition quote Hong Kong numbers, and British-founded chains quote letters. Ask for the inside diameter in millimetres and you sidestep the whole problem.
Malaysia. As in Singapore, US numbers dominate modern retail while traditional goldsmiths use Hong Kong numbers. Confirm the scale, or the diameter, before you order.
United Arab Emirates. Gulf retail quotes US sizes most often. British-founded chains use letters, and the many Indian gold houses in Dubai use the Indian scale, so the same finger can be quoted three ways along one street.
South Africa. South Africa follows the UK letter scale. Online stores that ship from the United States will quote numbers instead.
Brazil. Brazilian sizes are the inside circumference in millimetres minus 40 — the same arithmetic Switzerland uses. A 54 mm circumference is a Brazilian 14.
Mexico. Mexican jewellers use a local numeric scale that is not the US one, and the published conversions for it disagree with each other. We will not print a number we cannot stand behind, so order by inside diameter in millimetres, or ask the retailer for the diameter of the size they are offering. Large chains and online stores generally quote US sizes.
Questions
UK ring sizing, answered
What is the average ring size in the UK?
Around L to N for women and T to V for men. That is a starting point for a surprise, not a substitute for measuring the actual finger.
What is UK size N in US?
A US 6¾, an inside diameter of about 17.1 mm. UK L is roughly a US 5¾ and UK R roughly a US 8¾.
Are UK and Australian ring sizes the same?
Yes. Australia and New Zealand use the UK letter scale without modification, so a UK N is an Australian N.
How do I measure my ring size UK at home?
Measure the inside diameter of a ring that already fits and read the table above, or print the paper ring sizer at 100% and lay the ring over the circles. Measuring a ring beats measuring a finger, because a ring has one fixed diameter.
What does Z+1 mean?
The scale runs out of letters at Z, so the largest sizes continue as Z+1, Z+2 and so on, each a further half-letter step. They are ordinary sizes, just past the end of the alphabet.
Find your letter in about a minute
Calibrate your screen against a bank card, lay a ring you own on the glass, and read the letter straight off.