It is literally impossible, and I wish everyone was less stupid about how sizing works. Your chest measurement in total  is: cup size(A=1 inch B =2 inch..... so DD/E = 5 inches) plus your band size meaning the measurement around your chest which absolutely nothing to do with breast tissue, and everything to do with how fat you are So all these enormous cows who try to claim they're a "busty" 40 D that would mean their fat chest is 40 inches, and their boobs only account for 4 which is relatively nothing