Online Ring Sizer

Ring Size Converter

Choose a known ring size to see its reference measurements and approximate equivalents. No screen calibration is needed.

Quarter sizes are included where listed in the source chart. UK half letters are shown with ½.

Regional equivalents are approximate. Retailer charts can vary; blank source labels stay unavailable. EU / ISO is rounded circumference in millimetres, so one label can correspond to more than one reference row.

View our source and conversion rules

Have a physical measurement? Use the calculator · Measure a ring on your screen