Hello Ladies,

Often times during a fitting, I hear women exclaim “I’m a what?!” when I tell them the cup size portion of their measurement. “No, I can’t possibly be a (fill in the blank) cup!” Sound familiar? Part of this confusion arises from a long-standing misconception (propagated in part by the media) about how cup sizes relate to a woman’s boobs. The lovely and funny Sofia Vergara, for example, claims to wear a 34DD bra:

So, women (and men) associate a DD cup with Sofia’s ample chest or Salma Hayek’s or Jessica Simpson’s or . . . and the list continues.  One perusal of websites claiming to know “celebrity bra sizes” reveals similar seemingly large cup sizes for celebrities with bigger-than-average chests (Christina Hendricks is a 38DDD?  Are you being serious?).  For what seems like forever, cup sizes have been regarded in this way:

A’s are flat, B’s are small, C’s are average, D’s are big, DD’s are huge, and DDD’s are ridiculous.

The truth is, however, that cup sizes mean absolutely nothing on their own.  But, why?  Cup sizes are only one half an old married couple, and it is their long-suffering partner, the band size, that gives the cup size any kind of significance.  The little known fact to finding the right size bra is that cup sizes vary widely from one band size to another, i.e., a D is not a D is not a D.

Bras, like other fashion items, are built on the idea of scaling proportion, but the scale does not center on the cup—it’s the band that’s the star here.  The band of the bra is designed to represent your torso girth with everything from the width of the cups to the placement of the straps to the length of the wings shifting with each size so that every woman will get a customized fit.  As you step up in band size, the entire bra scales upward because the designer recognizes that the woman wearing this band is proportionally bigger than the woman who wears a smaller size.  This means that if a woman wears a band size too big for her, she will suffer from the underwire extending too far on her sides, a band that does not snugly support her breasts, straps that are too wide set, and proportionally bigger cups that require her to size down.

So, how do cup sizes factor in?  Simply put, they follow a pretty straightforward formula:

A = Band Size + 1, B = Band Size + 2, C = Band Size + 3, etc.

Nevertheless, because there is often a limited selection of sizes available, women will usually buy “cup size equivalent” bras—or bras whose sizes are vastly different but whose cups require the same amount of breast tissue.  For example, all of these sizes are cup-size equivalents:

28G = 30FF = 32F = 34DDD = 36DD = 38D = 40C

And here is the heart of why cup sizes mean absolutely nothing without a band size to define them.  The woman who wears a 28DD, for example, has less breast tissue than the woman who wears the 34DD.  In fact, a 34DD is cup size equivalent to 28FF!

To demonstrate how the band and cup size work together, let’s examine the DD cup:

28DD = 28″ ribcage, 33″ chest
30DD = 30″ ribcage, 35″ chest
32DD = 32″ ribcage, 37″ chest
34DD = 34″ ribcage, 39″ chest, etc.

Now, does Sofia Vergara really look like she has a 34″ ribcage and 39″ chest (roughly equivalent to a US size 12)?  I doubt it, and if I had to guess, I would say Sofia is probably closer to a 30HH in the above picture.

In closing, your band size is the most important aspect of your bra to fit perfectly because it provides over 80% of the support for your breasts and is the basis for the entire proportion of the bra.  All the cup size tells you is how deep a cup you need!

For more information on how band and cup sizing works, please check out our video blog on the subject!

Erica