Band size refers to the measurement around the torso, just under the bust, which helps determine the size of a bra. It is typically expressed in inches and is a crucial part of finding a well-fitting bra. For example, if the measurement is 32 inches, the band size would be labeled as 32. To calculate band size, one should measure the circumference of the ribcage just below the bust and round to the nearest whole number. If the measurement is an even number, add 4 inches; if it’s odd, add 5 inches. This final number represents the band size in the bra sizing system.