How to measure your ring size

Measure in millimetres

Use a ring that fits the same finger and measure its inside diameter, excluding the metal. Alternatively, measure the finger circumference without tightening the strip. Circumference = diameter × 3.1416.

Reference measurements

Diameters of 15.9, 16.6, 17.2, 17.8, 18.5, 19.1, 19.7 and 20.4 mm correspond to circumferences of approximately 50, 52.2, 54, 55.9, 58.1, 60, 61.9 and 64.1 mm. These are measurements, not universal US or UK size labels.

Confirm the fit

Temperature, swelling, knuckles and band width affect fit. Repeat the measurement and consult the brand’s chart. A wide ring may need a different fit. A jeweller’s measurement is preferable for an expensive purchase, and not every design can be resized.