Instant size tool
Ring Size Converter
Convert ring sizes instantly between US, UK, EU (diameter mm), and circumference (mm).
UK
EU
Diameter (mm)
Circumference (mm)
Full Size Chart
| US | UK | EU | Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|
| 3 | F | 44 | 14.1 | 44.2 |
| 3.5 | G | 45 | 14.5 | 45.5 |
| 4 | H | 46.5 | 14.9 | 46.8 |
| 4.5 | I | 47.5 | 15.3 | 48 |
| 5 | J½ | 49 | 15.7 | 49.3 |
| 5.5 | K½ | 50 | 16.1 | 50.6 |
| 6 | L½ | 51.5 | 16.5 | 51.9 |
| 6.5 | M½ | 52.5 | 16.9 | 53.1 |
| 7 | N½ | 54 | 17.3 | 54.4 |
| 7.5 | O½ | 55 | 17.7 | 55.7 |
| 8 | P½ | 56.5 | 18.1 | 57 |
| 8.5 | Q½ | 58 | 18.5 | 58.3 |
| 9 | R½ | 59 | 18.9 | 59.5 |
| 9.5 | S½ | 60.5 | 19.4 | 60.8 |
| 10 | T½ | 61.5 | 19.8 | 62.1 |
| 10.5 | U½ | 63 | 20.2 | 63.4 |
| 11 | V½ | 64 | 20.6 | 64.6 |
| 11.5 | W½ | 65.5 | 21 | 65.9 |
| 12 | X½ | 66.5 | 21.4 | 67.2 |
| 13 | Z½ | 69.5 | 22.2 | 69.7 |
How to Measure
Cut a thin strip of paper or a piece of string about 6 inches long. Wrap it snugly around the base of the finger you want to measure, without pulling too tight, and mark where the end meets the strip.
Lay the strip flat and measure the length from the start to your mark using a ruler in millimeters — this is your finger's circumference. Match it to the "Circumference (mm)" column above.
For the most reliable result, measure 2-3 times at the end of the day when your fingers are at their largest, and avoid measuring when your hands are cold.