A 28DD is small. VERY small. Its sister sizes are 30C and 32A. A 42DD is massive. The cup is relative to the band size.

How Bra Sizes Work: A Full Guide

Which bra size is bigger, 34C or 34D? - Quora

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Sister Sizes: The Bra Secret Every Person Should Know – Sister Sizes & Equivalent Bra Size Chart – ThirdLove

Sister Sizing De-Mystified! – Playful Promises USA

How Bra Sizes Work: A Full Guide

What do Bra Sizes Mean? – Curvy Kate CA

What is my bra size?

What is my bra size?

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