Measure the inside circumference of your finger, or the inside diameter of a ring that already fits you, and pick the matching size. Between two sizes? Choose the larger one.
| UKAUUS | EU | Circumference | Diameter |
|---|---|---|---|
| J½J½5 | 49 | 49.3 mm | 15.7 mm |
| L½L½6 | 52 | 51.9 mm | 16.5 mm |
| M½M½6.5 | 53 | 53.1 mm | 16.9 mm |
| N½N½7 | 54 | 54.4 mm | 17.3 mm |
| O½O½7.5 | 56 | 55.7 mm | 17.7 mm |
| P½P½8 | 57 | 57.0 mm | 18.1 mm |
| R½R½9 | 59 | 59.5 mm | 18.9 mm |
| T½T½10 | 62 | 62.1 mm | 19.8 mm |
| V½V½11 | 64 | 64.6 mm | 20.6 mm |
| X½X½12 | 67 | 67.2 mm | 21.4 mm |
| Z½Z½13 | 69 | 69.7 mm | 22.2 mm |
Inside circumference and inside diameter in mm. UK and AU letter sizes follow the British standard (BS 6820). The EU size is the inside circumference in mm.
How to measure
Your finger: wrap a strip of paper or a piece of thread around the base of your finger, mark where it meets and measure the length in mm with a ruler.
A ring that fits: measure the inside diameter of the ring straight across the middle.
Fingers are often slightly larger in the evening and in warm weather, so measure at the end of the day.