SIZE
STEP 1: BAND SIZE
Wrap a soft tape measure around your rib cage where your bra band typically sits (see image). Make sure the tape is level and not hiking up or falling back. If your under-bust measurement is even, add 2 inches. If odd, add 3 inches.
STEP 2: CUP SIZE
Wrap the tape measure around the fullest part of your bust. Make sure it's level and fits snugly. Subtract your band size from your bust. The difference determines your cup size (0 inches = AA cup, 1in = A cup, 2in = B cup, ect.)