The DD Dilemma: Core-Size vs. Full-Bust Bra Differences

  |   By Estelle Puleston

In the lingerie industry, bra sizing is broken down into categories. For example, ‘full bust’ sizing officially starts at a DD cup. Some full-bust brands choose to begin at D. ‘Core sized’ brands, on the other hand, traditionally focus on A-D cups. Nowadays, however, many such brands go up to a DD or even DDD. So there is some overlap.

I wear a DD cup size, which puts me right on the cusp between core and full-bust sizing. And I love it. I can shop at most full-bust brands, and yet still have my pick of many core-sized bras too. And when the brand stops at a D cup? I wear my sister size. I’m genuinely spoilt for choice!

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Having shopped in both bra categories for many years though, I’ve noticed some distinct differences between them. DD bras from core-sized and full-bust brands both fit me, insofar as I fill the cups out. But often, they look and feel different on my body.

Are you also one of the lucky ones who usually wear a DD cup? My guide below explains the key differences between a core-size DD and a full-bust DD.

full-bust bra

Persephone Full Cup Bra
 Available in sizes 30DD-38G
via Harlow & Fox

This bra, designed especially for full busts, has wide straps, seamed cups, side support panels, and a net lining behind the embroidery. I don’t think I’ve ever seen a core-sized bra with all four features.


A full-bust brand is going to be much more focused on support. For example, the underwires may be sturdier. It may have wider straps, which makes it less likely to dig in at the shoulders. And delicate or flexible fabrics will often come lined to prevent them from over-stretching.

Overall, you can typically expect less ‘bounce’ and a more secure feeling if you buy a full-bust DD. But that’s not always a good thing. I wear a DD cup on a small band size and don’t need tons of support. Sometimes I’m comfier in a less-structured bra with a bit more ‘give’!


I'm wearing a bra designed for B-E cups (left) and one designed for DD-G cups (right). Both bras are underwired, unlined, and fit me well.


A key support difference I didn’t mention above is seaming. Seams strengthen the cup, so full-bust brands utilize them much more frequently. Seams also change the shape of the cup. For example, horizontal seams allow the designer to create a deeper cup. This design feature lets your bust to project more.

Full-bust brands sometimes include ‘side supports’ in their bras too. These push that outer breast tissue inwards and forwards.

My 30DD bust can look relatively big, or pretty small. And it’s not due to whether my bra has padding. A core-sized bra often makes me look quite flat from the side. There’s not much shaping going on. Whereas a full-bust one pushes my bust upwards and forwards, making it look much rounder.

full-bust bras

You get can a DD cup at every mall in America. Victoria’s Secret bras, however, are not designed particularly with full busts in mind.


Over the past decade, there has been an explosion in the number of full-bust brands. Finding something supportive and stylish at a DD cup is no longer difficult.

That said, there are still far more brands that stop at a DD than start at it. You might need to shop online or go to a specialty boutique to find a wide selection of full-bust brands. But at the mall, there will always be plenty of core-sized ones.

And if you prefer to shop handmade? Bras with supportive features are harder and pricier to make. So naturally, the majority of independent designers steer clear of them. But if you want a cute bralette that only functions up to a DD, you’ll have your pick of hundreds.

Sarah Bra
 Available in sizes 30D-40G
via Tutti Rouge

Budget-friendly full bust brands do exist, but they are few and far between. And still pricier than picking up a DD at H&M!


As I mentioned, full-bust bras are more expensive to make. They have more parts, so take longer to sew. Their components may cost more, such as wider strap elastic. And more time/money is needed to develop the patterns in the first place.

They also use more fabric. Sure, two similar 32DD bras will use more or less the same amount. But brands don’t charge more for each cup size larger. Instead, they budget for the average fabric usage across their size range. And that’s higher for a DD-G size range than an A-DD one.

So while buying a DD bra from a full-bust brand has its advantages, do expect to pay a little more. On a tight budget? Then you’re probably better off looking at core-sized brands.

Fellow DD wearers, do you prefer to shop from core-size or full-bust brands? Or do you, like me, take full advantage and buy from both?

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