Cup size?

Cassidine

So my mom never really taught me how to measure for my bra size. I'm 20 now, and I keep running into the issue that my bras keep cutting into my sides and underboobs. I googled how to measure bra size, but I don't understand my cup size. My bust size is 48in and my band size is 40in. What does that make my cup size? 🥺