1. Measure around the chest directly under the breast at a constant height with the cloth measurement tape in centimeter, all the way around your back and ribcage.
2. Now measure around the chest at the height of the fullest part of the breast. The measuring tape should be held horizontal, flat on your back, and your arm should be at rest(down). Make a note of that measurement (only used for comparison) and compare it to the Bra Size at step 1.