MBLife.com uses US Size measurements.
Check the size of the measurement chart with your ruler.
Step 1: Print the circle table below with exact size. (Set printer as paper size of 100%)
Step 2: Place your current ring with appropriate size over the circles below, matching the inside edge of the ring to the circle nearest in size.
Step 3: Choose the larger size in case the rings falls between two sizes.
Ring Size Conversion Tool
Wrap a piece of string around your finger to measure the circumference. Measure the length of the string and look up your ring size using the table. You may also use the tool to convert your different measurements to the US ring sizes.