Ring size chart
A US size 7 ring has an inside diameter of about 17.3 mm (0.68 in) and a circumference of about 54.4 mm. Each half size adds about 0.4 mm of diameter.
Size converter
Measurements
| US size | Inside diameter | Circumference |
|---|---|---|
| 3 | 14.1 mm (0.554 in) | 44.2 mm |
| 3.5 | 14.5 mm (0.57 in) | 45.5 mm |
| 4 | 14.9 mm (0.586 in) | 46.8 mm |
| 4.5 | 15.3 mm (0.602 in) | 48 mm |
| 5 | 15.7 mm (0.618 in) | 49.3 mm |
| 5.5 | 16.1 mm (0.634 in) | 50.6 mm |
| 6 | 16.5 mm (0.65 in) | 51.9 mm |
| 6.5 | 16.9 mm (0.666 in) | 53.1 mm |
| 7 | 17.3 mm (0.682 in) | 54.4 mm |
| 7.5 | 17.7 mm (0.698 in) | 55.7 mm |
| 8 | 18.1 mm (0.714 in) | 57 mm |
| 8.5 | 18.5 mm (0.73 in) | 58.2 mm |
| 9 | 18.9 mm (0.746 in) | 59.5 mm |
| 9.5 | 19.4 mm (0.762 in) | 60.8 mm |
| 10 | 19.8 mm (0.778 in) | 62.1 mm |
| 10.5 | 20.2 mm (0.794 in) | 63.3 mm |
| 11 | 20.6 mm (0.81 in) | 64.6 mm |
| 11.5 | 21 mm (0.826 in) | 65.9 mm |
| 12 | 21.4 mm (0.842 in) | 67.2 mm |
| 12.5 | 21.8 mm (0.858 in) | 68.5 mm |
| 13 | 22.2 mm (0.874 in) | 69.7 mm |
What to know
To size a ring you already own, measure the inside diameter across the widest point with a ruler marked in millimeters. Wide bands fit tighter, so go up a half size for bands wider than about 6 mm.
Questions people ask
What is the average ring size?
Around 6 to 7 for women and 9 to 10 for men in the U.S.
Related sizes
Sources and method
- US ring size linear fit: diameter (mm) = 11.63 + 0.8128 × size
Imperial and metric values are converted with 1 in = 25.4 mm exactly and rounded only for display. Found a mistake? Report it and we will correct the page.