Did you know that the cup size 36C is smaller than a 40C and a 42C is bigger than a 34C?
As the band size changes, cup volume (size) changes. Each bra size has an underwire size for the proportionate increase or decrease in cup volume and band size. That is why it is very important that when you change your band size, you have to change the cup size, also. If you go up a band size, you have to go down a cup size. If you go down a band size, you have to go up a cup size. (34D and 36C have the same cup volume. 34D has a smaller cup volume than 36D.)