Find your ring size from finger circumference or diameter. Converts between US, UK, EU, and mm.
| US | UK | EU | Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|
| 5 | J | 49 | 15.7 | 49.3 |
| 6 | L | 52 | 16.5 | 51.8 |
| 7 | N | 54 | 17.3 | 54.4 |
| 8 | P | 57 | 18.1 | 57.0 |
| 9 | R | 59 | 18.9 | 59.5 |
| 10 | T | 62 | 19.8 | 62.1 |
Measure in the evening when fingers are at their largest. Avoid measuring when cold (fingers shrink) or after exercise (fingers swell).
Always round up to the larger size. It is easier to resize a ring down than up.
Measure your finger using a string/paper method or an existing ring. Enter the measurement in mm or inches. The calculator converts to US, UK, and EU ring sizes.
US Size = (Circumference in mm β 36.5) / 2.55. Diameter = Circumference / Ο. US size 7 = 17.3 mm diameter = 54.4 mm circumference.
Finger circumference 58 mm: US size 8.5, UK size QΒ½, EU size 58. Average women's size: US 6-7. Average men's size: US 9-10.
Measure at the end of the day when fingers are largest. Cold temperatures shrink fingers. The dominant hand is usually 0.5 size larger. For surprise rings, borrow one they wear on the ring finger to measure.