Measure your wrist all the way around with a fabric measuring tape.
Prefer a more snug fit? Order a half inch smaller than your wrist measurement.
Prefer a more loose fit? Order the exact size of your wrist.
For example, my wrist is 6 inches around but I prefer a 5.5 inch cuff because I don't like my bracelets to move around too much.
Bangles are a solid circle that you slip over your hand so it moves around on your wrist/arm.
If you currently own any bangles that fit well, measure the INSIDE diameter of those and that will be your size. Otherwise, squish your hand together as though you are putting on a bangle (see picture to the right), then measure around the widest portion of your hand with a fabric tape measure and divide that number by 3.14 for your size.
It won't be terribly accurate, but will give you an idea. For example, I wear a size 2.5 but my measurement comes out to 2.38-2.46.
If you're measuring in cm: (Inch = cm / 2.54). Please contact me if you need help.