Use a flexible tape measure. No tape measure? Wrap a strip of paper around your wrist or neck, mark where the ends meet, then measure that length flat with a ruler in inches or cm.
| Size | Diameter (mm) | Circumference (mm) | US Size |
|---|---|---|---|
| 14 / US 4 | 14.9 | 46.8 | 4 |
| 15 / US 5 | 15.7 | 49.3 | 5 |
| 16 / US 6 | 16.5 | 51.9 | 6 |
| 17 / US 7 | 17.3 | 54.5 | 7 |
| 18 / US 8 | 18.2 | 57.2 | 8 |
| 19 / US 9 | 19.1 | 59.9 | 9 |
| 20 / US 10 | 19.8 | 62.2 | 10 |