Ring sizes are measured differently in every country, but they all describe the same thing: the inside of the ring. This guide from KAMBO Jewelry shows how to find your size and how to convert it between US, UK, EU, Turkish and Japanese sizes, with the inner diameter and circumference in millimeters.
How to find your ring size
Best way: have your finger measured at a jeweler. Any local jeweler can measure your finger with a professional ring sizer in a minute, usually free of charge. This is the most reliable method. Then tell us your size in any system: US, UK, EU, Turkish, Japanese, or the inner diameter in mm.
Alternative: measure a ring that already fits. Put a ring that fits the right finger on a ruler and measure the inside diameter, from inner edge to inner edge, in millimeters. Find that diameter in the chart below.
Fingers are smaller in the cold and in the morning, so have your size checked when your hands are warm. If you are between two sizes, choose the larger one.
International ring size chart
| US / Canada | UK / Australia | EU (circumference) | Turkey | Japan | Inner diameter (mm) | Circumference (mm) |
|---|---|---|---|---|---|---|
| 3 | F | 44 | 4 | 4 | 14.1 | 44.2 |
| 4 | H | 47 | 7 | 7 | 14.9 | 46.8 |
| 4½ | I | 48 | 8 | 8 | 15.3 | 48.0 |
| 5 | J½ | 49 | 9 | 9 | 15.7 | 49.3 |
| 5½ | K½ | 51 | 11 | 11 | 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 | 16 | 17.7 | 55.7 |
| 8 | P½ | 57 | 17 | 17 | 18.1 | 57.0 |
| 8½ | Q½ | 58 | 18 | 18 | 18.5 | 58.2 |
| 9 | R½ | 60 | 20 | 20 | 18.9 | 59.5 |
| 9½ | S½ | 61 | 21 | 21 | 19.4 | 60.8 |
| 10 | T½ | 62 | 22 | 22 | 19.8 | 62.1 |
| 10½ | U½ | 63 | 23 | 23 | 20.2 | 63.3 |
| 11 | V½ | 65 | 25 | 25 | 20.6 | 64.6 |
| 11½ | W½ | 66 | 26 | 26 | 21.0 | 65.9 |
| 12 | X½ | 67 | 27 | 27 | 21.4 | 67.2 |
| 12½ | Z | 68 | 28 | 28 | 21.8 | 68.5 |
| 13 | Z+1 | 70 | 30 | 30 | 22.2 | 69.7 |
| 13½ | — | 71 | 31 | 31 | 22.6 | 71.0 |
| 14 | — | 72 | 32 | 32 | 23.0 | 72.3 |
| 15 | — | 75 | 35 | 35 | 23.8 | 74.8 |
Values are rounded. Turkish and Japanese sizes both equal the circumference in millimeters minus 40. The EU size is the circumference in millimeters.
Quick rules for converting between systems
- EU size = inner circumference in mm. EU 56 means 56 mm around the inside.
- Turkish and Japanese size = circumference in mm − 40. EU 56 is Turkish 16 and Japanese 16.
- UK letters fall between US half sizes. A UK letter without "½" sits a quarter size below the matching US size: UK P is about US 7¾, UK R is about US 8¾.
- From diameter to circumference: multiply by 3.14. A 22 mm inner diameter is about 69 mm around, which is US 12¾, EU 69, Turkish 29.
Tips for the right fit
- Wide bands fit tighter. For a band 8 mm or wider, which is common in men's signet and gemstone rings, go up half a US size.
- Large knuckles: ask the jeweler to check that the ring slides over the knuckle. Choose a size that slides on but does not spin.
- Thumb and index rings are usually 2–4 US sizes larger than ring-finger sizes.
- Not sure? Send us the inner diameter of a ring that fits, in mm. We make every ring to order and can match it exactly.
Frequently asked questions
How do I convert a UK letter ring size to a US size?
UK letters sit between US half sizes. A letter with "½" matches a US size exactly (UK N½ = US 7, UK P½ = US 8), and a plain letter is about a quarter size smaller (UK P ≈ US 7¾, UK R ≈ US 8¾).
What ring size is 22 mm inner diameter?
A 22 mm inner diameter is about 69 mm in circumference. That is roughly US 12¾, EU 69, Turkish 29 and Japanese 29.
How are Turkish ring sizes calculated?
The Turkish ring size is the inner circumference in millimeters minus 40. For example, a ring with a 56 mm circumference is Turkish size 16, which is about US 7½.
What is the difference between EU and US ring sizes?
The EU size is simply the inner circumference in millimeters, while the US size follows its own number scale. EU 54 is about US 7, EU 57 is about US 8, and EU 62 is about US 10.
Should I size up for a wide ring?
Yes. For bands 8 mm or wider, choose about half a US size larger, because a wide ring covers more of the finger and feels tighter.
Can KAMBO make a ring in any size?
Yes. KAMBO Jewelry handcrafts every ring to order in Türkiye, so we can make any size, including quarter sizes and large men's sizes. Send your size in any system or the inner diameter in mm.