Chest size is a singular measurement, while bust size considers band and cup measurements for bra fitting accuracy. Bra sizing complexity arises from the need to account for both band and cup measurements . Sister sizes maintain the same cup volume but vary in band and cup measurements , highlighting the relative nature of bra sizing. Bust Size Calculator, your ultimate tool for precise bra and clothing measurements . Learn how to determine band size and cup size for the perfect fit, supported by industry tips and a handy size chart. Bra-wearers can calculate their cup size by finding the difference between their bust size and their band size. [61][63] The bust size, bust line measure, or over- bust measure is the measurement around the torso over the fullest part of the breasts, with the crest of the breast halfway between the elbow and shoulder, [64] usually over the ... Record your overbust and underbust measurements and refer to the bra size chart below to know your correct size amongst the list of bra sizes. Alternatively, you can find your perfect fit with our 2 minutes bra fit test.