Start with your band size and wear a lightly lined (non-push-up) bra.Place the measuring tape around your ribcage, directly under your bustensuring that the tape is straight.
Now measure your bust. Place the tape at the fullest part of your bustMake sure it is parallel to your band.
Subtract your band size from your cup size. Count each inch of difference as one cup size.
Find the final number to get your CUP SIZE. Your BRA SIZE is your BAND SIZE plus your CUP SIZE.