Convert ring sizes between US, UK, Europe, Japan, and measure inside diameter & circumference.
Converted Sizes & Dimensions
USA / Canada
6.0
UK / Australia
L 1/2
Europe / ISO
52
Japan / China
11
Diameter (mm)
16.5 mm
Circumference (mm)
51.9 mm
📏 How to Determine Your Ring Size
Wrap a non-stretchy strip of paper or string around the base of your finger.
Mark the exact point where the two ends overlap with a pen.
Measure the length of the paper strip against a ruler (in millimeters) to get your finger's Circumference.
Divide the circumference by 3.14 (π) to get the internal Diameter.
Compare your measurement against the international chart below.
⚠️ Safety Tips & Measurement Precautions
Crucial factors before choosing a ring size:
Temperature Effect: Cold weather causes fingers to shrink, while heat, high humidity, or heavy exercise causes swelling. Always measure your finger at normal room temperature at the end of the day.
Knuckle Clearance: If your knuckle is significantly larger than the base of your finger, measure both the knuckle and base, then choose a size halfway between them so the ring slips over comfortably.
Ring Width Matters: Wider band rings (over 6mm) feel tighter than thin band rings. If buying a wide band, select half a size larger (+0.5 US).
Dominant Hand Size: Your dominant hand is usually half a size larger than your non-dominant hand. Never assume both hands share identical measurements.
String Stretch Caution: Avoid elastic materials or yarn when measuring, as they stretch easily and cause inaccurate sizing. Use paper strip or thread.