| Interior diameter / inside circumference | Circumference (mm) | |
| Size | ||
| 3 | 14.1 | 44.2 |
| 3.5 | 14.5 | 45.5 |
| 4 | 14.9 | 46.8 |
| 4.5 | 15.3 | 48 |
| 5 | 15.7 | 49.3 |
| 5.5 | 16.1 | 50.6 |
| 6 | 16.5 | 51.9 |
| 6.5 | 16.9 | 53.1 |
| 7 | 17.3 | 54.4 |
| 7.5 | 17.7 | 55.7 |
| 8 | 18.1 | 57 |
| 8.5 | 18.5 | 58.3 |
| 9 | 18.9 | 59.5 |
| 9.5 | 19.4 | 60.8 |
| 10 | 19.8 | 62.1 |
| 10.5 | 20.2 | 63.4 |
| 11 | 20.6 | 64.6 |
| 11.5 | 21 | 65.9 |
| 12 | 21.4 | 67.2 |
| 12.5 | 21.8 | 68.5 |
| 13 | 22.2 | 69.7 |
Find Your Ring Size
Measure Your Finger
- Use a flexible measuring tape or length of string.
- Wrap it around the finger you’ll wear your ring on—if you’re creating a ring stack, consider where on your finger the ring will sit. If using string, mark the point on the string where the ends meet with a pen.
- Lay the string on a flat surface and use a ruler to measure the length (in inches or millimeters) up to the mark. Compare your measurement to the Tiffany size chart above to determine your ring size. If you are between sizes, opt for the larger size.