First, let’s go over the basics. Your bra size is made up of your band size and your cup size. According to British lingerie brand Katherine Hamilton, the band size refers to the size of your ...

But buying a new bra? You probably dread the day you ... Here’s where the math comes in. In order to determine your cup size, ...

This is because a 12D and a 16D differ in band size, and the cup size adjusts accordingly. "Your bra size can change as you gain or lose weight throughout different stages of your life.