Three ways — pick the one that fits your situation.
Inside diameter and finger circumference for every size. Highlighted rows are the most common range.
| US Size | Diameter (mm) | Circumference (mm) | Notes |
|---|---|---|---|
| 3 | 14.1 | 44.2 | Very small / petite fingers |
| 3.5 | 14.5 | 45.5 | |
| 4 | 14.9 | 46.8 | Slender fingers |
| 4.5 | 15.3 | 48.0 | |
| 5 | 15.7 | 49.3 | |
| 5.5 | 16.1 | 50.6 | |
| 6 | 16.5 | 51.9 | Most common US average |
| 6.5 | 16.9 | 53.1 | Most common |
| 7 | 17.3 | 54.4 | Most common |
| 7.5 | 17.7 | 55.7 | |
| 8 | 18.2 | 57.2 | Larger fingers |
| 8.5 | 18.6 | 58.3 | |
| 9 | 19.0 | 59.7 | Larger fingers |
| 9.5 | 19.4 | 61.0 | |
| 10 | 19.8 | 62.2 | Larger fingers |
| 10.5 | 20.2 | 63.5 | |
| 11 | 20.6 | 64.8 | |
| 11.5 | 21.0 | 66.0 | |
| 12 | 21.4 | 67.3 | Very large fingers |
If guessing a partner's size, 6.5 is the single safest estimate. When between sizes, always choose the larger.