Why 30DD Gets Mis-sized as 32C in Most Stores

The vast majority of chain retailers use the outdated "+4 method" of bra fitting, where they add four inches to your underbust measurement before calculating cup size. For a true 30DD with a 30-inch underbust and 35-inch bust, this method results in a 34-inch band with a 1-inch difference -- producing a completely incorrect 34A or, with some manipulation, a 32C.

This means a woman who genuinely needs a 30DD often walks out of a department store wearing a 34B or 32C. The band is too loose to provide proper support, so the straps end up carrying all the weight, leading to shoulder grooves, back pain, and poor breast tissue support over time.

If you have been wearing a 32C and notice that your band rides up in the back, your straps dig into your shoulders, or your breasts spill out of the cups when you scoop and swoop, there is a good chance a 30DD is your actual size. A simple at-home measurement can confirm whether you have been mis-sized.