| Size (US) | Diameter (mm) | Circumference (mm) | Diameter (inches) | Circumference (inches) |
|---|---|---|---|---|
| 5 | 15.7 | 49.3 | 0.62 | 1.94 |
| 5.5 | 16.1 | 50.6 | 0.63 | 1.99 |
| 6 | 16.5 | 51.9 | 0.65 | 2.04 |
| 6.5 | 16.9 | 53.1 | 0.67 | 2.09 |
| 7 | 17.3 | 54.4 | 0.68 | 2.14 |
| 7.5 | 17.7 | 55.7 | 0.7 | 2.19 |
| 8 | 18.1 | 57 | 0.71 | 2.24 |
| 8.5 | 18.5 | 58.3 | 0.73 | 2.29 |
| 9 | 18.9 | 59.5 | 0.75 | 2.34 |
| 9.5 | 19.4 | 60.8 | 0.76 | 2.39 |
| 10 | 19.8 | 62.1 | 0.78 | 2.44 |
| 10.5 | 20.2 | 63.4 | 0.79 | 2.49 |
| 11 | 20.6 | 64.6 | 0.81 | 2.54 |
| 11.5 | 21 | 65.9 | 0.83 | 2.59 |
| 12 | 21.4 | 67.2 | 0.84 | 2.64 |
| 12.5 | 21.8 | 68.5 | 0.86 | 2.7 |
| 13 | 22.2 | 69.7 | 0.87 | 2.75 |
| 13.5 | 22.6 | 71 | 0.89 | 2.8 |
| 14 | 23 | 72.3 | 0.91 | 2.85 |
| 14.5 | 23.4 | 73.6 | 0.92 | 2.9 |
| 15 | 23.8 | 74.8 | 0.94 | 2.95 |
Notes:
• Rings 10mm or wider feel tighter than a same size thinner ring.
• Measurements above are of the inside of the ring.