Size Studio
UK Ring Size X in US, EU and mm
A UK (and Australian) ring size X is about a US 11.75 and an EU 66, with an inside diameter of about 21.1 mm (66.3 mm around).
| US / CA | UK / AU | EU (ISO) | Japan | Inside diameter | Inside circumference |
|---|---|---|---|---|---|
| 11.75 | X | 66 | 25 | 21.1 mm | 66.3 mm |
Good to know
- EU (ISO) ring sizes are the inside circumference in millimetres. US sizes go up about 0.8 mm in diameter per whole size, UK letters about 0.4 mm.
- Fingers swell when warm. Measure at the end of the day, and go half a size up for wide bands.
Sizes either side
Smaller: WLarger: YOpen the full converterHow to measure yourself
Questions
What is ring size X in mm?
About 21.1 mm inside diameter, 66.3 mm around.
What is UK ring size X in US?
About US 11.75.
What is ring size X in EU?
EU 66.
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