For the cup size:
1. Measure loosely around the fullest part of your bust, with the tape straight across and around your back, bringing it to the front.
2. Subtract your band measurement (from step 1) from this bust measurement. The difference calculates your bra size- each inch represents a cup size. For example, if you measure a 34 inch band size, and a 36 inch cup size, the difference is 2: which would indicate a B cup.