What is Ring Sizing?
Ring sizing is the standardized measurement of the inner circumference of a ring. However, standards vary globally. The US uses numbers, the UK uses letters, and Europe uses millimeters. Our AI-enhanced tool acts as a universal translator for these systems.
How to Measure Ring Size at Home?
You do not need a jeweler to get an accurate number. Follow the String Method:
Wrap a piece of string or paper around the base of your finger. It should be snug but not tight.
Mark the point where the ends meet with a pen.
Lay the string flat and measure the length in millimeters. Enter this into the calculator.
If your knuckle is significantly larger than the base of your finger, measure both and pick a size in between. Our calculator rounds to the nearest comfortable fit based on jewelry tolerances.
International Size Conversion Table
| Circumference (mm) | US / Canada | UK / Australia | EU / ISO |
|---|---|---|---|
| 49.3 mm | 5 | J ½ | 49 |
| 51.9 mm | 6 | L ½ | 52 |
| 54.4 mm | 7 | N ½ | 54 |
| 57.0 mm | 8 | P ½ | 57 |
| 59.5 mm | 9 | R ½ | 60 |
Frequently Asked Questions
Can I measure an existing ring?
Yes. Measure the inside diameter of a ring that fits you well. Multiply that number by 3.14 (Pi) to get the circumference, then enter it into the calculator.
What if I am between sizes?
Always size up. It is much easier to wear a slightly loose ring or add a sizing bead than to wear a ring that cuts off circulation.
Disclaimer
This AI Ring Size Calculator provides estimates based on standard international conversion charts. Ring fit can vary by manufacturer, ring width, and individual finger shape. For expensive purchases, we recommend visiting a local jeweler for professional sizing.