Ring Size Guide — US, UK & EU
Ring sizes vary by country. The US uses a numbered scale, the UK uses letters, and Europe measures inner circumference in mm. Use this chart to convert between all three systems and find your exact fit.
How to Measure Your Ring Size
Ring Size Conversion Chart
| US / Canada | UK / Aus / NZ | EU / FR / DE | Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|
| 3 | F | 44 | 14.1 | 44.2 |
| 3.5 | G | 45 | 14.5 | 45.5 |
| 4 | H | 47 | 14.9 | 46.8 |
| 4.5 | I | 48 | 15.3 | 48.0 |
| 5 | J½ | 49 | 15.7 | 49.3 |
| 5.5 | K½ | 50 | 16.1 | 50.6 |
| 6 | L½ | 52 | 16.5 | 51.9 |
| 6.5 | M½ | 53 | 16.9 | 53.1 |
| 7 | N½ | 54 | 17.3 | 54.4 |
| 7.5 | O½ | 56 | 17.7 | 55.7 |
| 8 | P½ | 57 | 18.1 | 57.0 |
| 8.5 | Q½ | 58 | 18.5 | 58.3 |
| 9 | R½ | 59 | 18.9 | 59.5 |
| 9.5 | S½ | 61 | 19.4 | 60.8 |
| 10 | T½ | 62 | 19.8 | 62.1 |
| 10.5 | U½ | 63 | 20.2 | 63.4 |
| 11 | V½ | 65 | 20.6 | 64.6 |
| 11.5 | W½ | 66 | 21.0 | 65.9 |
| 12 | X½ | 67 | 21.4 | 67.2 |
| 13 | Z | 70 | 22.2 | 69.7 |
Frequently Asked Questions
How do I measure my ring size at home?
The most accurate method: wrap a thin strip of paper or string around the base of your finger, mark where it overlaps, measure the length in mm — that is your circumference. Divide by π (3.14159) to get your diameter, then find it in the table above. Measure at the end of the day when fingers are slightly swollen for the best fit.
What is the most common ring size for women?
In the US, the average women's ring size is 6 to 6.5 (diameter 16.5–16.9 mm, EU 52–53). For men, the average is 9 to 10 (diameter 18.9–19.8 mm, EU 59–62).
How do I convert US ring size to EU?
EU ring sizes equal the inner circumference in mm, rounded to the nearest whole number. US size 6 ≈ EU 52, US size 7 ≈ EU 54, US size 8 ≈ EU 57. Use the table above for exact conversions.
How do I convert US ring size to UK?
UK ring sizes use letters (A–Z). US size 5 = UK J½, US size 6 = UK L½, US size 7 = UK N½, US size 8 = UK P½. Half sizes exist in UK sizing — see the full table above.
What is the difference between ring diameter and circumference?
The diameter is the straight-line distance across the inside of the ring (in mm). The circumference is the distance around the inside (inner circumference in mm = diameter × π ≈ diameter × 3.14159). EU and Japanese ring sizes are based on circumference; US/Canada sizes use a numbered scale.
Can I use a ruler to measure my ring size?
Yes. Place an existing ring flat on a ruler and measure the inside diameter in mm. Find that diameter in the table above to get your size. Alternatively, use this online ruler — calibrate it to your screen and measure the ring directly on screen.