Easy as A,B,C… The Bra Fitting Basics

By Linda the Bra Lady on July 21st, 2010

When is a D cup not a D cup? Bra Fitting Basics

32A, 40D, 34DDD, 38B … We all recognize a bra size when we see it. But do you know what these numbers and letters actually mean? You’d be surprised how many women don’t know the basics of bra fitting – and you may even be one of them!

What does Band Size Mean?

The number portion of your bra size is your band size. This number relates to your “underbust” – the spot right under your breasts where your bra band should lie. The wider this part of your body is, the higher your band size will be. Notice that your band size has nothing to do with how large your breasts are. It will correspond roughly to your weight or dress size.

What does Cup Size Mean?

The letter after your band size is your cup size. The cup size tells you the difference between the size of your breasts and the size of your ribcage. This brings me to a very important bra fitting tip: as the band size gets bigger, the cup gets bigger too. For example, a 36B bra has bigger cups than a 34B bra. If you go down to a smaller band size, your cup size has to go up if you want the same amount of space in the cup. So a 36B bra has the same size cup as a 34C bra.

With this in mind, don’t get too hung up on your cup size. Some women are shocked or upset when they find out they’re a AA or DD or G cup. In reality, the cup size is almost meaningless without the band size. Buy bras that make you look and feel great and don’t worry about the size on the tag. Nobody will know but you and me!
For more help determining the best bra size for you, visit my online Bra School or give us a call at 1-888-262-4887. We’re always happy to help.

Stay fabulous!


  1. […] On the one hand, this is a useful tidbit of bra size knowledge. Many women don’t realize that the cup size changes based on the size of the band, and this goes a long way in explaining bra size confusion. It illustrates, for example, why someone with a 30DD bra size might not look like a stereotypical “DD” and someone with a 42A won’t look like an “A” cup. (See Easy As A, B, C… The Bra Fitting Basics) […]

  2. […] on what you are currently wearing. If the band feels tight, go up a band size, but remember that when you go down a band size, you’ll have to go up in the cup. If you are spilling out of the cups, keep going up cup sizes until you can fit all of your breast […]