Ring Sizer
Print check: the bar below is exactly 50 mm. Print at 100 percent (Actual Size), turn off "Fit to page", then measure the bar with a ruler before you use this sheet. If it is not 50 mm, the circles and strip will be the wrong size.
The small box beside it is 10 mm.Part A: measure a ring you own
Drop a ring over the circles until one matches its inside edge. The label gives your US size and the ISO/EU number (the inner circumference in millimetres).
- US 3 · ISO/EU 44 · 14.1 mm
- US 4 · ISO/EU 47 · 14.9 mm
- US 5 · ISO/EU 49 · 15.7 mm
- US 6 · ISO/EU 52 · 16.5 mm
- US 7 · ISO/EU 54 · 17.3 mm
- US 8 · ISO/EU 57 · 18.1 mm
- US 9 · ISO/EU 60 · 18.9 mm
- US 10 · ISO/EU 62 · 19.8 mm
- US 11 · ISO/EU 65 · 20.6 mm
- US 12 · ISO/EU 67 · 21.4 mm
- US 13 · ISO/EU 70 · 22.2 mm
- US 14 · ISO/EU 72 · 23 mm
Part B: measure a finger
Wrap the strip around the base of the finger, mark where it overlaps, and read the millimetres. That reading is the inner circumference, which is your ISO and Continental-European ring number directly.
Measure at the end of the day, when the hand is warm: a finger can swell close to a full size between a cold morning and a hot afternoon. For a band wider than 6 mm, go up about a half size.
The strip reading in millimetres is your ISO and EU size. Find US, UK, Japan and other systems at convertsizes.com/rings/.