Ring Size Converter
Convert ring sizes between US, UK, EU, and millimeter (inner diameter) measurement systems.
Inner Diameter (mm)
14.9 mm
Formula
## Ring Size Conversion Ring sizes vary by country. The US system uses numbers (typically 3-16), while the UK uses letters and EU uses circumference in mm minus 40. ### Approximate Formula **Diameter (mm) = 11.63 + (US Size - 3) x 0.814** **Circumference = Diameter x pi** **EU Size = Circumference - 40** ### Quick Reference | US | Diameter (mm) | EU | |---|---|---| | 5 | 15.7 | 49 | | 7 | 17.3 | 54 | | 9 | 19.0 | 60 |
Exemplo Resolvido
Convert US size 7 to other systems.
- 01Diameter = 11.63 + (7-3) x 0.814 = 14.886 mm
- 02Wait, let me recalculate: 11.63 + 4 x 0.814 = 14.886 mm
- 03Circumference = 14.886 x pi = 46.76 mm
- 04EU size = 46.76 - 40 = ~7
Perguntas Frequentes
How do I measure my ring size?
Wrap a thin strip of paper around your finger, mark where it overlaps, and measure the length in mm. This is the circumference. Divide by pi for diameter, then use a size chart.
Do ring sizes differ by width?
Yes. Wider bands fit tighter, so you may need a half-size to full-size larger for bands wider than 6mm compared to standard 2-4mm bands.
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