Sister Sizing refers to bras that have the same cup volume, but have different band sizes. It’s common for busty women to own more than one bra size.

First consider all the different bra manufactures. They all cut and frame their bras in their own unique way.  And within their realm, they also will offer different styles. For example, a convertible Bali bra size 36D can fit much differently than the Comfort U Bali of the same size. And when you try on a Goddess strapless convertible bra of the same size, you may find their bands run a bit larger. So you could try on a 34D and discover the band is comfortable, but the cup is a bit smaller. That’s because the cup volume is different.

Most women think that all D cups hold exactly the same volume of breast tissue, and that the cup size is standard and simply sewn onto different lengths of band to make the 30D, 32D, 34D etc. This is not true. My best example is this: If you look at a 32D cup, it’s a much smaller cup than a 38D cup. That’s because as the band size increases, so does the cup. Even though the bra says D cup, the volume changes as the band increases. Refer to the chart.

Combined with the fact that there isn’t a standard or universal sizing method used by all bra manufactures, and many bras that are made for bustier women are not manufactured in the US, this certainly makes for some frustrating times in the dressing room.

But, now that you are armed with this knowledge, possibly bra shopping will be a bit easier!  Please stop by Little Black Box for a professional bra fitting, we look forward to seeing you!