Exact ring size conversion

EU ring size 66.5

EU size 66.5 is equivalent to US size 12, with an inside diameter of approximately 21.4 mm.

Inside diameter21.4 mm
Inside circumference67.2 mm

How to check EU size 66.5

Measure the inside diameter of a ring that already fits the intended finger. Measure straight across the widest inside point—do not include the metal. Compare that measurement with 21.4 mm.

This is a jewellery-size conversion, not a guarantee of fit. Finger size changes with temperature and time of day; wide bands often need extra room.

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