Ring Size Chart
A ring size chart lists each size with its inner diameter and circumference in millimetres, so any scale can be read against any other. Type a ring’s inner diameter or your finger’s circumference into the finder for your size on every scale; the chart below marks the nearest row. An inner diameter of 16.5 mm, for example, is US 6, UK L½, EU 52.
Your size
US 6
UK L½ · EU 52 · Japan 12
- US / Canada 6 (exact)
- UK / Australia L½ (exact)
- EU / ISO 52 (exact)
- Japan 12 (−0.5 mm)
- Inner diameter 16.5 mm (0.65 in)
- Inner circumference 51.8 mm (2.04 in)
| US | Diameter mm | Circumference mm | UK | EU / ISO | Japan |
|---|---|---|---|---|---|
| 3 | 14.07 | 44.2 | F½ | 44 | 4 |
| 3½ | 14.47 | 45.5 | G½ | 45.5 | 5 |
| 4 | 14.88 | 46.8 | H½ | 47 | 7 |
| 4½ | 15.29 | 48 | I½ | 48 | 8 |
| 5 | 15.69 | 49.3 | J½ | 49.5 | 9 |
| 5½ | 16.1 | 50.6 | K½ | 50.5 | 10 |
| 6 ◀ | 16.51 | 51.9 | L½ | 52 | 12 |
| 6½ | 16.91 | 53.1 | M½ | 53 | 13 |
| 7 | 17.32 | 54.4 | N½ | 54.5 | 14 |
| 7½ | 17.73 | 55.7 | O½ | 55.5 | 15 |
| 8 | 18.13 | 57 | P½ | 57 | 16 |
| 8½ | 18.54 | 58.2 | Q½ | 58 | 18 |
| 9 | 18.95 | 59.5 | R½ | 59.5 | 19 |
| 9½ | 19.35 | 60.8 | S½ | 61 | 20 |
| 10 | 19.76 | 62.1 | T½ | 62 | 21 |
| 10½ | 20.16 | 63.3 | U½ | 63.5 | 22 |
| 11 | 20.57 | 64.6 | V½ | 64.5 | 24 |
| 11½ | 20.98 | 65.9 | W½ | 66 | 25 |
| 12 | 21.38 | 67.2 | X½ | 67 | 26 |
| 12½ | 21.79 | 68.5 | Z | 68.5 | 27 |
| 13 | 22.2 | 69.7 | Z+1 | 69.5 | 29 |
| 13½ | 22.6 | 71 | Z+2 | 71 | 30 |
| 14 | 23.01 | 72.3 | Z+3 | 72.5 | 31 |
| 14½ | 23.42 | 73.6 | Z+4 | 73.5 | 32 |
| 15 | 23.82 | 74.8 | Z+5 | 75 | 33 |
How are the sizes on the chart worked out?
Inner circumference = π × inner diameter. US size: diameter in mm = 11.63 + 0.8128 × size. UK: circumference = 37.5 + 1.25 × letter (A = 0). EU / ISO: the circumference itself. Japan: diameter = 13 + (size − 1) ÷ 3.
Worked example. An inner diameter of 16.5 mm is a circumference of π × 16.5 = 51.84 mm. On the US scale, (16.5 − 11.63) ÷ 0.8128 = 5.99, so the nearest quarter size is US 6. On the UK scale, (51.84 − 37.5) ÷ 1.25 = 11.47, nearest letter L½. EU is the circumference, 52. Japan: (16.5 − 13) × 3 + 1 = 11.5, nearest 12.
US 7, one of the two most common women’s sizes, is 17.32 mm across and 54.4 mm around.
Reading the chart
Each row is one US size at its exact diameter and circumference; the UK, EU and Japanese columns give the nearest size on those scales. Where a UK half size is skipped between two rows, that is the scales’ spacing, not an error: US half sizes step 1.28 mm around, UK half sizes 0.625 mm, EU sizes 1 mm. Above Z the UK scale continues as Z+1, Z+2 and so on. For a size that falls between rows, use the finder, which shows the gap.
Diameter or circumference?
Measure a ring by its inner diameter: the widest distance across the inside of the band, which a ruler can read directly. Measure a finger by its circumference: the length of a strip wrapped round it. The two are linked by π, so the chart shows both for every row, and the finder takes either.
Before you buy
A size from a chart is a strong estimate; a jeweller’s steel gauge is the final word, and most jewellers resize a plain band by a size or two. For a wide band (6 mm or more), go up a quarter to half size; for a ring that must pass a large knuckle, see the fit guide. The printable sizer gives true-size circles to lay a ring on when you have no ruler.
Questions about ring sizes
How do I find my ring size from a ring I already have?
Measure the inside of the band at its widest, in millimetres, with a ruler or callipers, and type it into the finder as the inner diameter. 16.5 mm is a US 6; 17.3 mm is a US 7; 18.9 mm is a US 9. The on-screen sizer does the same with the ring laid on your phone.
How do I find my ring size without a ring?
Wrap a strip of paper or string snugly round the finger, mark where it overlaps, measure the length and type it in as the circumference. 54 mm around is US 6¾, close to a 7. The measuring page walks through it and checks the knuckle.
Which countries use which scale?
US sizes in the United States, Canada and Mexico; letters in the UK, Ireland, Australia and New Zealand; the circumference in mm (ISO 8653) across most of Europe; a numbered scale in Japan, China and much of East Asia. The guide explains each.
Why do charts on different sites disagree by a size?
Because each scale is defined its own way and sizes rarely land exactly on one another. US 6 is 51.9 mm around; UK L is 51.25 and L½ is 51.9, so a chart may say L or L½. Our chart shows the nearest size and how far off it is, so you can see when you are between two.
What is the most common ring size?
US 6 to 7 for women and 9 to 10 for men, by what jewellers sell. US 6 is 16.5 mm across; US 10 is 19.8 mm. See the average ring size page.
Does my ring size change?
Yes, by up to half a size through the day and across seasons: fingers are larger in the evening, in heat and after salt or alcohol, smaller in the cold and the morning. Measure at the end of a normal day at room temperature, more than once.