A ring size calculator provides a helpful estimate based on the measurement you enter. For everyday purchases it is usually a good guide, but for important purchases like an engagement ring, a physical measurement with a professional ring sizer or jeweler is recommended for extra confidence.

The paper-strip method is the simplest approach. Wrap a thin strip of paper or non-stretch string around the base of the finger, mark where it overlaps, then measure that length in millimeters and enter it into the calculator above.

Fingers naturally change size slightly throughout the day due to temperature and activity. Measuring in the evening, when fingers tend to be at their normal size and hands are at a comfortable temperature, generally gives a more consistent result.

If your measurement falls between two standard sizes, consider how you like a ring to fit and the width of the band. A slightly looser fit or a wider band may favor the larger size, while a snug, everyday-wear preference may favor the smaller one.

Yes. Wider bands cover more surface area of the finger and can feel tighter than a narrow band in the same labeled size, so many people size up slightly for wide bands.

Yes. Choose a ring that already fits the intended finger comfortably, measure the inside diameter from one inner edge to the opposite inner edge, and enter that measurement using the “Measure an Existing Ring” method above.

No, sizing systems differ by region. The US and Canada use a numeric scale, the UK and Australia use letters, the EU uses a millimeter-based numeric scale, and Japan uses its own numeric scale. Use the converter tab above to move between them.

There isn’t one universal “most common” size — average ring size varies by market, region and individual hand size. Measuring your own finger, rather than relying on a general average, will give you a far more useful starting point.