What is ring size 10 in mm?

US ring size 10 is 19.8 mm inner diameter and 62.1 mm circumference (EU 62.1, UK T½, Japan 20).

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Ring size 10 in mm

Inner Ø19.8mm

Circumference62.1mm = EU/ISO

UKT½

JP · CN20

IT · ES · CH22.1

US ring size 10 has an inner diameter of 19.8 mm and an inner circumference of 62.1 mm. The EU/ISO size is that circumference (62.1); in the UK it’s T½, in Japan/China 20, and in Italy/Spain/Switzerland 22.1 (circumference minus 40). Not sure of your size? Measure a ring you own with the on-screen ring sizer.