Reference · Japan
Japanese ring size chart
Japanese sizes are whole numbers written with a hash — #9, #13, #21 — running from #1 to about #27 across the range people actually wear. Each step is a little under half a US size. The table below gives every one as an inside diameter in millimetres, with the US, UK and EU equivalents beside it.
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The table
Japanese ring sizes in mm
Japanese numeric sizes against inside diameter and circumference, with the US number, UK letter, EU circumference and Indian size on the same row.
| Japan | Ø mm | Circ. mm | US / CA | UK / AU | EU / ISO | India |
|---|---|---|---|---|---|---|
| #2 | 13.3 | 41.6 | 2 | D | 42 | 2 |
| #3 | 13.7 | 42.9 | 2½ | E | 43 | 3 |
| #4 | 14.1 | 44.2 | 3 | F | 44 | 4 |
| #5 | 14.5 | 45.5 | 3½ | G | 45 | 5 |
| #6 | 14.9 | 46.8 | 4 | H | 47 | 7 |
| #8 | 15.3 | 48.0 | 4½ | I | 48 | 8 |
| #9 | 15.7 | 49.3 | 5 | J | 49 | 9 |
| #10 | 16.1 | 50.6 | 5½ | K | 51 | 11 |
| #11 | 16.5 | 51.9 | 6 | L | 52 | 12 |
| #13 | 16.9 | 53.1 | 6½ | M | 53 | 13 |
| #14 | 17.3 | 54.4 | 7 | N | 54 | 14 |
| #15 | 17.7 | 55.7 | 7½ | O | 56 | 15 |
| #16 | 18.1 | 57.0 | 8 | P | 57 | 17 |
| #17 | 18.5 | 58.2 | 8½ | Q | 58 | 18 |
| #18 | 18.9 | 59.5 | 9 | R | 60 | 19 |
| #19 | 19.4 | 60.8 | 9½ | S | 61 | 21 |
| #21 | 19.8 | 62.1 | 10 | T | 62 | 22 |
| #22 | 20.2 | 63.3 | 10½ | U | 63 | 23 |
| #23 | 20.6 | 64.6 | 11 | V | 65 | 25 |
| #24 | 21.0 | 65.9 | 11½ | W | 66 | 26 |
| #25 | 21.4 | 67.2 | 12 | X | 67 | 27 |
| #27 | 21.8 | 68.5 | 12½ | Y | 68 | 28 |
| #28 | 22.2 | 69.7 | 13 | Z | 70 | 30 |
Derived from ISO 8653. Japanese sizes are ordinarily whole numbers, so a measurement between two rows rounds up.
How the Japanese scale works
The scale is numeric and close to linear, at roughly 0.33 mm of inside diameter per step. That puts about 2.4 Japanese sizes to one US size, so the Japanese numbers climb faster than American ones — a US 6 is a #12, a US 8 is a #16, and a US 10 is a #20.
Half sizes are not part of the standard range. If your measurement lands between #13 and #14, take #14: a ring slightly loose can be beaded, one that will not pass the knuckle cannot be worn while you decide.
Japanese jewellery houses — Mikimoto, Tasaki, 4°C — quote this scale at home and often quote the local scale abroad, so the same ring can carry two numbers depending on where you buy it. Both describe the same inside diameter.
Ordering from Japan
Marketplace listings from Japan usually give the Japanese number alone. Convert it here, or better, convert in the other direction: measure the inside diameter of a ring that already fits and find the Japanese number for it, so the measurement rather than a conversion is what you are relying on.
If a listing gives a diameter in millimetres, use that and ignore the size number entirely. The international ring size chart covers all five scales, and the Mikimoto size chart goes further on pearl rings, which size differently from plain bands.
Getting it right
Three things to know about Japanese sizes
- Whole numbers only
- The standard range has no half sizes. Round up when a measurement falls between two numbers.
- The numbers climb faster
- About 2.4 Japanese steps to one US size. A one-number error is smaller here than it looks, but three is a full size.
- Pearl rings size snug
- Weight sitting above the band makes a slightly loose ring rotate on the finger. Size close, while still clearing the knuckle.
Ordering from elsewhere
The same finger in another market
Japan, China and Hong Kong all number their sizes differently from one another despite the visual similarity. Pick the market you are buying from.
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
Japanese ring sizing, answered
What is Japanese ring size 13 in US?
About a US 6½ — an inside diameter of roughly 16.9 mm.
What is the average ring size in Japan?
Around #11 to #13 for women and #20 to #22 for men, which is roughly US 6 to 6.5 and US 10 to 11.
Do Japanese rings come in half sizes?
Rarely. The standard scale is whole numbers, so round up when you are between two.
Are Japanese and Chinese ring sizes the same?
No. Mainland Chinese listings usually quote the inside circumference in millimetres, and Hong Kong uses its own numbered scale. All three look like plain numbers and none of them convert into each other directly — check the millimetre.
How do I measure a Japanese ring size at home?
Measure the inside diameter of a ring that already fits, on a calibrated screen or with a caliper, then read the Japanese column above.
Measure the diameter, read the #
The sizer calibrates your screen against a bank card first, so the circle you match your ring to is a real millimetre wide.