Find Your Correct Bra Size
Calculate your bra size from band and bust measurements. Includes sister sizes and fitting tips.
How to Measure Your Bra Size
Band measurement: Wrap a tape measure snugly around your ribcage, directly under your bust. Round to the nearest even number — this is your band size. Bust measurement: Measure around the fullest part of your bust (usually at nipple level), keeping the tape parallel to the floor. Don't pull tight — let it rest naturally. Cup size: Subtract band from bust. Each inch of difference = one cup size (1" = A, 2" = B, 3" = C, 4" = D, 5" = DD).
Sister Sizes
Sister sizes have the same cup volume but different band sizes. If 34C is slightly tight in the band, try 36B (same cup volume, looser band). If 34C is loose in the band, try 32D (same cup volume, tighter band). This is useful when: a brand doesn't carry your exact size, an online order doesn't fit perfectly, or you're between sizes. About 80% of women wear the wrong bra size — most are wearing a band too large and a cup too small.
An estimated 80% of women wear an incorrect bra size. The most common error: wearing a band that is too loose and a cup that is too small. A properly fitted bra should get most of its support from the band (80%), not the straps (20%). If your straps are doing the heavy lifting and digging into your shoulders, your band is too big.
