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The Ring Size Converter translates ring sizes between major international sizing systems: US (3-13 with half sizes), UK (alphabetical F-Z½), EU/ISO (44-70), Japan (4-27), and mm diameter or circumference. Each system measures the inner diameter of the ring differently, making conversion essential for international jewelry shopping. The calculator uses standard ISO 8653 reference tables for accurate conversion.
Formule
- D
- Inner Diameter (mm) — Ring opening width measured inside
- C
- Inner Circumference (mm) — Length around inside of ring
Stapsgewijze handleiding
- 1Enter your known ring size and select source system
- 2Calculator finds closest match in international reference table
- 3Outputs all equivalent sizes plus mm diameter and circumference
- 4Use mm circumference for most accurate measurement (wrap string method)
- 5Round up if between sizes — easier to resize down than up
Uitgewerkte voorbeelden
Veelgemaakte fouten om te vermijden
- ✕Measuring outer ring diameter — must be inner; standard sizing systems all reference inner diameter
- ✕Measuring cold fingers — fingers swell 5-10% throughout the day; measure mid-afternoon
- ✕Using string measurement loose — pull snug but not tight against finger base
- ✕Forgetting wider bands need larger sizes — 6mm+ wide bands require +1/2 size
Veelgestelde vragen
How do I measure my ring size at home?
Wrap a thin string snugly around your finger's base, mark where it overlaps, measure in mm. That's your circumference; divide by π (≈3.14) for diameter. Use afternoon measurement for accuracy — fingers swell throughout day.
What if I'm between sizes?
Round up for everyday rings (easier to resize down). For tight bands that won't resize, round down. For wide bands (≥6mm), automatically add ½ size to compensate for less flex.
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