To measure for a C cup size, you’ll need two key measurements: your band size and your bust size. First, measure your band size by wrapping a soft measuring tape snugly around your ribcage, just below your bust, ensuring the tape is level. Round to the nearest whole number and add 4 inches if the number is even or 5 inches if it’s odd (e.g., 30 inches becomes 34). Next, measure your bust size by wrapping the tape around the fullest part of your chest, keeping it straight but not too tight. Subtract your band size from your bust size to determine your cup size. A 1-inch difference equals an A cup, 2 inches equals a B cup, and a 3-inch difference equals a C cup.