Everyone has a unique body type, which means sometimes you may not find accurate bra size measurement using the regular bra size chart. Here, you can switch to sister sizes. Basically, these are alternate bra sizes where the cup volume stays the same even though the band size and cup letter change. For instance, if you are a 34 B, there is a good chance that a 32 C or a 36 A will fit you. 32 C will have a shorter band size and 36 A will have a longer one, so you can figure out what fits you better.