US, ISO / Europe, and UK sizes are among the most commonly used ring size systems for international orders. This chart compares these systems by inside diameter in millimeters.

 

Please use the inside diameter values as the main reference when comparing sizes. If you are unsure of your size, please let me know the size system used in your country or region, and I will confirm it carefully before production.

 

Note: UK size intervals are not completely uniform, so some adjacent sizes may appear close together in the chart.