The cup size of a bra is determined by the difference - Band to Bust – BRABAR

The cup size of a bra is determined by the difference between the rib cage measurement and the overbust measurement, so a 28DD size bra is 28 inch rib cage and 34 inch overbust measurement because 28 inch (rib cage) + 6 inch (difference) = 34 (overbust). Therefore, the cup size in this case would be DD. A 32D bra size.

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