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Inches to Ring Size (US, UK, EU & Japan)

Convert an inside diameter or circumference in inches to ring sizes. You get matching US, UK, EU, and Japan sizes plus the millimeter equivalent.

Estimates for general information, verify important figures before relying on them.
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Common values

Inside diameterCircumferenceUS size
0.618 in1.94 in4
0.650 in2.04 in5.5
0.682 in2.14 in7
0.714 in2.24 in8.5

Common questions

How do I measure my ring size at home?

Measure the inside diameter of a ring that fits, in inches, then convert it here. Measuring circumference with a strip of paper also works.

Are US and UK ring sizes the same?

No. The US uses numbers and the UK uses letters, so a US 7 is roughly a UK N, which is why a multi-region chart helps.

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