Ring sizer

Find your ring size

Not calibrated

Put a ring you already own flat on the screen and match it to a circle. Measure the inside edge, not the band.

Tap a circle to read off every sizing scale.

Full conversion chart
Ring sizes in US, UK, ISO, millimetres and inches
US UK ISO mm in
3 F 44.2 14.07 0.55
3.5 n/a 45.5 14.47 0.57
4 H 46.8 14.88 0.59
4.5 n/a 48.0 15.29 0.60
5 J½ 49.3 15.69 0.62
5.5 n/a 50.6 16.10 0.63
6 L½ 51.9 16.51 0.65
6.5 n/a 53.1 16.91 0.67
7 N½ 54.4 17.32 0.68
7.5 n/a 55.7 17.73 0.70
8 P½ 57.0 18.13 0.71
8.5 n/a 58.2 18.54 0.73
9 R½ 59.5 18.95 0.75
9.5 n/a 60.8 19.35 0.76
10 T½ 62.1 19.76 0.78
10.5 n/a 63.3 20.16 0.79
11 V½ 64.6 20.57 0.81
11.5 n/a 65.9 20.98 0.83
12 X½ 67.2 21.38 0.84
12.5 n/a 68.5 21.79 0.86
13 Z½ 69.7 22.20 0.87

Full size guide and calibrated ruler

Calibrate your screen

Hold a real object against the screen and drag the slider until the outline matches it exactly. A bank card is the surest reference, because every one is the same size by standard, but if you have measured something yourself, pick Something else and type its width. The result is stored on your device only, and you do it once.

Screen density: 96 DPI

No card to hand? Estimate from your screen size

Tell us your screen's advertised size, meaning the number printed on the box, measured corner to corner. From that and the resolution your browser reports we can work out the density. It handles display scaling and external monitors correctly, which guessing your device from a list does not. It is still an estimate, because an advertised diagonal is a nominal figure, so matching a card stays the only route to a verified reading.

Enter or pick a size to see the estimate.