Fine Jewelry Sizing Guide
Interactive Ring Size Converter & Chart
Accurately convert ring sizes between US, UK, European, and Japanese standards with millimeter inner diameter measurements.
UK / Australia
M 1/2
Europe / ISO
53.0
Japan / Asia
13
Inner Diameter (mm)
16.9 mm
Expert Tips for Accurate Ring Sizing
- Measure at Room Temperature: Fingers expand in heat and shrink in cold. Measure at normal room temperature towards the end of the day.
- Account for Knuckles: If your knuckle is significantly wider than the base of your finger, measure both and choose a half-size in between so the ring slides over comfortably.
- Band Width Consideration: Wider bands (over 4mm) fit more snugly; master jewelers recommend going up half a size for wide cigar bands or eternity bridal sets.