Ring Size Calculator
Enter inner diameter or finger circumference in millimeters to estimate the closest US, UK, EU, JP, and CN ring size.
Using diameter
Measure the inside opening of a ring that already fits. Keep the ruler straight through the widest point.
Using circumference
Wrap paper or string around the finger, mark the overlap, and measure the length flat in millimeters.
This tool provides an estimated ring size only. Double-check before buying, especially for expensive, custom, or engagement rings.
FAQ
Common questions
How accurate is this ring size tool?
It provides an estimated ring size. Screen calibration, browser zoom, ring alignment, and measuring method can all affect the result.
Can I measure ring size on my phone?
Yes. A phone is often easier because you can place a ring directly on the screen after calibration.
What if I am between two sizes?
Check the fit with another method. Wider bands can feel tighter, so many buyers choose the larger nearby size for wide rings.
Should I use this for an engagement ring?
Use it as a starting point only. For expensive, custom, or engagement rings, confirm with a professional jeweler.