A sewing tape measure can be used to measure the circumference of the finger by wrapping the tape around the finger. Make sure you leave enough room for the tape measure to slide the knuckles of the finger. If buying for someone else, you could also ‘borrow’ one of their rings and use a tape to measure the inside circumference.
| Ring size | Circumference (mm) |
|---|---|
| I | 48.0 |
| J | 48.7 |
| K | 50.0 |
| L | 51.2 |
| M | 52.5 |
| N | 53.8 |
| O | 55.1 |
| P | 56.3 |
| Q | 57.6 |
| R | 58.9 |
