What is the biggest C cup bra size?

The size of a C cup bra can vary between bra brands and styles, but generally, it refers to a breast volume that is larger than a B cup and smaller than a D cup. In terms of measurements, a C cup typically corresponds to a difference of 3 inches between the band size (the measurement under the bust) and the bust measurement. For example, if the band size is 34 inches, a C cup would mean the bust measurement is 37 inches. The "biggest" C cup would depend on the band size it is paired with, as larger band sizes will have larger overall breast volumes.