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Ring size chart
| US & Canada | UK & Australia | EU / ISO | Swiss / IT / ES | Japan | Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|---|---|
| 3 | F½ | 44 | 4 | 4 | 14.1 | 44.2 |
| 3½ | G½ | 45 | 5 | 5 | 14.5 | 45.5 |
| 4 | H½ | 47 | 7 | 7 | 14.9 | 46.8 |
| 4½ | I½ | 48 | 8 | 8 | 15.3 | 48.0 |
| 5 | J½ | 49 | 9 | 9 | 15.7 | 49.3 |
| 5½ | K½ | 51 | 11 | 10 | 16.1 | 50.6 |
| 6 | L½ | 52 | 12 | 12 | 16.5 | 51.9 |
| 6½ | M½ | 53 | 13 | 13 | 16.9 | 53.1 |
| 7 | N½ | 54 | 14 | 14 | 17.3 | 54.4 |
| 7½ | O½ | 56 | 16 | 15 | 17.7 | 55.7 |
| 8 | P½ | 57 | 17 | 16 | 18.1 | 57.0 |
| 8½ | Q½ | 58 | 18 | 18 | 18.5 | 58.2 |
| 9 | R½ | 60 | 20 | 19 | 18.9 | 59.5 |
| 9½ | S½ | 61 | 21 | 20 | 19.4 | 60.8 |
| 10 | T½ | 62 | 22 | 21 | 19.8 | 62.1 |
| 10½ | U½ | 63 | 23 | 22 | 20.2 | 63.3 |
| 11 | V½ | 65 | 25 | 24 | 20.6 | 64.6 |
| 11½ | W½ | 66 | 26 | 25 | 21.0 | 65.9 |
| 12 | X½ | 67 | 27 | 26 | 21.4 | 67.2 |
| 12½ | Z | 68 | 28 | 27 | 21.8 | 68.5 |
| 13 | Z+1 | 70 | 30 | 29 | 22.2 | 69.7 |
How the sizes are defined
RingSizeChart converts every size to the inside circumference in millimetres and finds the nearest size in each system:
- US and Canada: size 0 is 0.458 in (11.63 mm) across and each size adds 0.032 in (0.8128 mm), in quarter sizes. Circumference is about 36.5 mm + 2.55 mm × size.
- UK, Ireland, Australia and New Zealand (BS 6820): letters with half sizes, 1.25 mm of circumference per letter from A = 37.5 mm to Z = 68.75 mm, then Z+1, Z+2 and so on.
- EU / ISO 8653: the inside circumference in mm, so size 54 is 54 mm around. Used in France, Belgium, Austria and the Nordic countries.
- Switzerland, Italy and Spain: the circumference minus 40 mm, so size 14 is 54 mm.
- Germany and the Netherlands: the inside diameter in mm.
- Japan: the customary scale, 13 mm across for size 1 and ⅓ mm more per size. Japanese and Asian retailers' charts can differ by a size.
Sizes in different systems rarely line up exactly, and jewellers' charts differ by up to half a size. Fit also depends on band width, comfort-fit profiles and temperature. For an expensive ring, have your finger sized by a jeweller.
Frequently asked questions
What is a US size 7 in mm?
About 17.3 mm inside diameter and 54.4 mm inside circumference: UK N½, EU 54.
What is the most common ring size?
Commonly quoted averages are around US 6 to 7 for women and 9 to 10 for men.
Are ring sizes the same everywhere?
No. The US, UK, Europe, Switzerland and Japan each use their own scale, so convert through millimetres.
Is RingSizeChart free?
Yes, with no sign-up or ads.
Is my size saved?
Yes, in this browser only.