mm to ring size
Measured your finger in mm? A 54 mm inner circumference is a US 7.
Circumference (mm) to ring size
| Circumference | Inner Ø | US | UK |
|---|---|---|---|
| 49.3 mm | 15.7 mm | 5 | J½ |
| 51.9 mm | 16.5 mm | 6 | L½ |
| 54.4 mm | 17.3 mm | 7 | N½ |
| 57.0 mm | 18.1 mm | 8 | Q |
| 59.5 mm | 18.9 mm | 9 | R½ |
| 62.1 mm | 19.8 mm | 10 | T½ |
The EU/ISO ring size is the inner circumference in mm, so 54 mm circumference is an EU 54. Measured diameter instead? Multiply by π (3.14) for circumference.
Frequently asked questions
What ring size is 54 mm?
A US 7 (UK N½, EU 54).
How do I convert mm to ring size?
If you measured circumference, the mm value is the EU size. If diameter, multiply by 3.14 first.