Ring size 12 in millimetres

US ring size 12 is 21.39 mm inner diameter and 67.2 mm circumference.

21.39 mm inner Ø
Proportional only — actual on-screen size depends on your display.
US / CA
12
UK / AU
Y
EU / ISO
67
Japan
25
CH / IT / ES
27
Ø in
0.842
50 mm reference
Actual-size print check Inner diameter: 21.39 mm. Print at 100% and verify the 50 mm reference bar before comparing a ring.

This is around the average men’s ring size (US 9–10). See the full international ring size chart · Converter

Convert size 12: UK · EU · Japan

Frequently asked questions

What is ring size 12 in mm?

US ring size 12 has an inner diameter of 21.39 mm and an inner circumference of 67.2 mm.

What is US 12 in UK, EU and Japan ring sizes?

US 12 converts to UK Y, EU/ISO 67, Japan 25, and Switzerland/Italy/Spain 27.

Is ring size 12 small or large?

This is around the average men’s ring size (US 9–10).