DD Is Average and More Bra Basics
Let's talk about the alphabet. When I tell people that I wear a size DD, they immediatley look at my chest and say, "No way!" To which I reply, "Honey, cup sizes go up to M." We've been led to believe that DD is the end of the lingerie alphabet. There's also a stigma associated with those two letters. "No, I can't be a DD. That's HUGE!" women say.
Here are the facts: DD is average. According to a poll by lingerie retailer Rigby & Peller, the average American bra size is a 34DD. (Note: This poll was done back in 2013, and I suspect that the average size has likely increased since then.) The chart below can give you a better idea of the range of sizes available, from a 28AA to a 52M. And to be honest, there are niche brands that go up to 58 band and down to AAA cups.
As you can see, bra sizing is extensive, and much more complicated that S, M, L or size 0-22. Each size is made up of a band measurement (that's the number) and a cup measurement (that's the letter). These numbers work together like a ratio to come up with your unique bra size.
Some DDs are bigger than others.
OK, so this is where it gets confusing. All DDs are not the same cup size. A DD can be bigger or smaller based on the band. Remember, they work together as a ratio. Here's a graphic by lingerie blogger Fairy BoobMother that explains it better.
As you can see in this illustration, as the band size gets bigger the cup volume also gets bigger. So a 32DD is smaller than a 42DD. When the cup increases and the band stays the same, the cup volume also increases. So, a 30F is bigger than a 30D. You need both a number and letter to truly know your bra size.
Once you find your bra size, it's easy to find your sister size.
My bra size is a 32E, but I can also wear a 30F or a 34DD. That's because all these bras have different band sizes but the same cup volume. It's an easy formula. When you go up in the band, go down in the cup. When you go down in the band, go up in the cup. Here's a continuation of the graphic by the Fairy BoobMother.
Your sister size is helpful because all bra brands fit differently. Some run small in the band, some run large in the cups. If you're out shopping and your typical bra size doesn't quite fit or the shop doesn't have your exact size, try one of your sister sizes.
To make this even more complicated, every country does bra sizing differently.
There is no standard way of measuring bra sizes, which is a pain in the a**. On The Underline Life, I'll primarily be sticking to UK sizing because the majority of brands that are geared to DD+ are UK based. I've made it a habit to measure myself or get measured every time I buy a new bra online or in store—just to be sure.
One last note about full bust versus full figure versus plus size.
You'll see me write about "full bust" bras a lot here on The Underline Life. Full bust is the term the lingerie industry uses to categorize women with small band and large cup size. So, anyone with a DD cup or larger and a 36 band or less is considered "full bust." That includes sizes like 28G, 30F, 32E (like me), and 34H.
Plus size is a category more used by the fashion industry, and it covers dress sizes 14 and up. In bra sizes that translates to band sizes 38 or larger. There's another subset of this category called full figure. Full figure encompasses sizes DD+ with a 38 or larger band. Not all plus-size women fit into the full figure category. A 38F would be considered full figure and plus size. But a 40B would be just plus size.
If you've gotten this far, you understand that bra sizing is complicated.
The good news: I want to help make it simpler. Let me know if you have any questions in the comments below.