A 30DD is not necessarily big, but it does indicate a fuller cup with a smaller band size. Since bra sizes are relative, 30DD bras have about the same cup volume as a 32D or 34C, just with a tighter band for more support.

What bra size is equivalent to 30DD?

A 30DD is equivalent to a 32D, 34C, or 28E in terms of cup volume. However, because different brands use varying sizing systems, using HerRoom’s Universal Cup Sizing™ (UCS) helps find the best fit.

30DD Bras, Swimwear & Lingerie | 200+ Brands

Bra sizing can be confusing, especially with different international standards. 30DD lingerie and swimwear in US sizing is equivalent to a 30E in European brands like Chantelle, Empreinte, and Prima Donna. That’s why HerRoom created the Universal Cup Sizing™ (UCS) system, which helps you shop across different brands with ease. By searching for 30D2, you’ll find all the bras and swimwear that match your size, whether the label says DD or E.