How to know the perfect size for your new rings?

Here on SUB_° the ring sizes are always indicated in mm of DIAMETER.

If you don't know the size of the ring you want to buy, here's how to find out!

1) Take a ring already at your disposal with a ruler (or with any measuring tape) measure the diameter of the ring, I recommend measuring only the internal diameter measured in the center!

2) The second method involves downloading the 'Ring sizer' app. Simply place a ring you already have on your phone and obtain the diameter.

3) This last method will be useful if you don't have a ring in your size. Take a tape measure and measure the circumference of your finger (if you don't have a tape measure, take any type of thread, roll it around your finger and make a mark where the points join). Tighten the thread or tape measure very tightly to take the measurement as precisely as possible. Measure its length in centimeters. Consult the table shown here.

Once you have obtained the diameter in centimeters, simply select the conversion in millimeters as the measurement!


  • diameter 1.7cm = 17mm
  • diameter 2cm = 20mm
  • diameter 1.9cm = 19mm