What ring size is 20 mm?
A 20 mm inner diameter is a US 10.5 — UK U½, EU 63, Japan 22. (between sizes — we suggest sizing up)
- US
- 10.5
- UK
- U½
- EU
- 63
- Japan
- 22
- Inner diameter, millimetres
- 20
- Circ mm
- 62.8
Explore
See the full international ring size chart · Converter
Frequently asked questions
Is 20 mm a diameter or circumference?
On this page 20 mm is the inner diameter (the width across the inside of the ring). The matching inner circumference is about 62.8 mm.
I am between sizes — should I size up or down?
Measure again at a different time. If the result stays between sizes, compare band width, knuckle clearance, and the retailer's chart before choosing. A wider band can feel tighter than a narrow one at the same labelled size.
How should I confirm a converted ring size before ordering?
Measure the same finger or a ring that fits with a second method. For an expensive, wide, or non-resizable ring, check the retailer's chart and confirm with a physical sizer or jeweller.