Sister sizes: bra sizing chart. Cup sizes are not only volume, but also shape, and that's what makes the difference. Someone wearing a 32DD has the same amount of breast tissue as someone wearing a 42AAA, but they would appear flat-chested whereas the one in the DD would seem bigger. No wonder we can never find bras that fit!
Everything You Never Knew You Needed To Know About Bras. PIN THIS NOW AND GO MEASURE YOURSELF! CasaDiMoo says, "For years, I used the (horribly incorrect) store method of bra sizing and had straps that slid, armpit fat, quad boob, etc. Then I stumbled across this method about three years ago, and realized I was a 34HH and not a 38DD. My girls, and back, are thankful!"