Ring Size
Measure a well-fitting ring, distinguish diameter from circumference, and use the size chart. Learn when to confirm your ring size with a jeweller.
Find your ring size
How do you find the right ring size? Measure the inside diameter of a ring worn on the same finger and hand, compare it with the size chart, then confirm the fit with a jeweller, especially for a wide band. Measure your ring size on screen with the ring size finder - it calibrates against any credit card, so there is nothing to print. GIA ring-size guide (opens in new tab).
The table itself sits on its own page, where it has room to be read on a phone: the ring size chart by country sets the US, UK, European and Asian systems side by side, with the diameter and circumference in millimetres for each.
How to measure an existing ring
Choose a round ring that fits the intended finger on the same hand. Lay it flat and measure straight across the centre, from one inside edge to the other, in millimetres. Do not include the metal band. Repeat the measurement and look up the inside diameter in the size chart.
Diameter is the distance across the opening; circumference is the distance around its inside. They are different measurements. If you measured across a ring, use the diameter column, not the circumference column. A national size number is not necessarily a measurement in millimetres. For example, an inside diameter of 16.5 mm corresponds to a 51.8 mm circumference and US size 6 in the ring size chart.
One-minute buyer case
Check the fit before ordering
A ring should pass over the knuckle and sit comfortably at the base of the finger. If you have no suitable ring, use a proper finger sizer or ask a jeweller to measure you. String can stretch, and paper measurements can be inaccurate. Check again when your hands are at a normal temperature.
Between sizes, getting inconsistent results, or choosing a wide band? Confirm the fit with a jeweller using a band of similar width. For a surprise gift, an existing ring is only useful if you know which finger and hand it fits. Check the seller’s resizing policy before ordering; not every design can be resized. Compare ring designs once you have a reliable measurement.
Your next decision
- If a ring already fits the intended finger: record its inside diameter with the size finder and cross-check the number in the size chart. Keep the measurement, not just a national size label.
- If measurements disagree, the band is wide, or the gift is a surprise: confirm with a jeweller using a similar-width band and check the seller’s resizing policy before ordering.
