What ring size is 21 mm?
A 21 mm inner diameter is a US 11.5 — UK W½, EU 66, Japan 24.
- US
- 11.5
- UK
- W½
- EU
- 66
- Japan
- 24
- Ø mm
- 21
- Circ mm
- 66.0
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Frequently asked questions
What ring size is 21 mm?
A 21 mm inner diameter is closest to US 11.5 (UK W½, EU 66, Japan 24).
Is 21 mm a diameter or circumference?
On this page 21 mm is the inner diameter (the width across the inside of the ring). The matching inner circumference is about 66.0 mm.