Just wrap the soft tape measure around the broadest part of your wrist and take note of the length. If you are using a plain strip of paper, mark your size with a pen or pencil then use a ruler to measure the length (The starting end of the paper must be at the base of the ruler and marked 0). That would be your wrist size.

Please make sure there's enough space to tuck in 2 fingers as this is the space you need to add the charms. If you want to add less than seven charms, add 2 centimeters are ok. If you plan to wear eight or more charms, please add 3 centimeters. If you purchase a bangle, just choose the next size from your actual wrist measurement.