cm to mm Ring Size Converter

Your details

Circumference: wrap a thin strip of paper around your finger, mark where it meets, then measure the strip. Diameter: place a ring flat and measure across the inside.
Enter your measurement in centimetres. Typical adult finger circumferences range from about 4.2 cm (very small) to 7.0 cm (very large).
cm
CircumferenceSmall (US 5-6)
51.9mm

Inside circumference in millimetres

Circumference5.19cm
Diameter1.652cm
Diameter16.52mm
US / Canada size6
UK / Australia sizeM
France / Russia size52 3/4
Germany size16 1/2
Switzerland size12
Japan size12 3/4
51.9 mm
Very small<45Small45-52Medium52-60Large60-67XL67+

Your ring size is approximately US 6 / UK M.

  • Your finger circumference is 51.9 mm (5.19 cm) with an inside diameter of 16.52 mm.
  • Your US size is 6. Sizes in other standards: UK M, France/Russia 52 3/4, Germany 16 1/2, Japan 12 3/4.
  • If you are between two sizes on the chart, choose the larger one - a ring that is slightly loose is easier to resize than one that is too tight.
  • Finger size changes slightly throughout the day (larger in the afternoon, smaller in the morning) and with temperature. Measure at the end of the day for the most accurate fit.

Next stepIf ordering online from an international jeweller, use the circumference in mm (French/Russian system) or the diameter in mm (German system) as these are the most universally unambiguous measurements.

 = Powered by OnlyCalculators