Michelle, fashion blogger of The Pretty Year, has recently written some excellent explanations of the relationship between bra band sizes and cup letters – I just had to share them with you! We have touched on this topic in our bra sizing guide, but Michelle discusses this specific aspect in-depth. First, she tackled the basics and started her readers out with a quiz.
Question #1: Which of these bras is bigger in cup size?
Question #2: Okay, which of these bras has the bigger cup size?
Question #3: How about these bad boys?
Think you know the answers? You may be surprised! Head on over to The Pretty Year’s post Size Chart Woes: The Naked Truth About Bra Sizes to check your answers and to learn more about the band/cup relationship, the myth of “sister sizing,” and cup size illusions.
Then, in a follow-up post, she said,
…there seems to be a major discrepancy between What We Were All Taught about bra sizing and Bra Reality.
Basically, we were told that cup size is determined by the number of inches difference between our underbust and bust measurements– 1 inch = A cup, 2 inches = B cup, and so on. Based on this, many of us assumed this meant that all A cups were the same size/volume (i.e., “1 cubic inch” or some such), all B cups were the same size/volume, etc., and that the only difference between, say, a 32D and a 36D was in the band. But nay, as our own photographic evidence suggests, this is not true. Your 36D has significantly more volume in the cup than your 32D, in addition to being wider in the band itself.
A dramatic reenactment:
To learn why a 1 inch difference in perimiter equals more than a 1 inch difference in cup volume (with more helpful visualizations) go to Size Chart Woes: Fun With Math!