Measure your correct bra size to ensure proper fit.  Almost 2/3 of all woman do not wear the right bra size.  Proper fit will provide support, maximize cleavage, and enhance clothing.  The fullest measurement should be used for clothing size charts.

Use a flexible (cloth or vinyl) measuring tape (available at fabric stores).  Either measure while naked or in a loose slip/camisole.  Do not pull the tape tight.  Begin and end the tape measure along the side of your body, so you can glance down to read it.  It is also helpful to have the numbers upside down.   

If you do not trust your own measurements, Victoria's Secret stores provide this service.

1. BAND SIZE:  Measure under the breasts along chest wall and straight across the back.  Round up to the nearest whole number.  Now add 5 to that measurement for the band size.  Example, measure 29 + 5 = 34 band size. Measure 30.5 + 5 = 35.5 or 36 band size.

2. CUP SIZE:   Measure the fullest part of the breast and across the back without compressing the breasts.  0" difference = AAA,  1" difference = AA,  2" difference = A,  3" difference = B,  4" difference = C,  5" difference = D,  6" difference = DD

Correct bra size will help you buy other garments with confidence, such as swimsuits, gowns and formal dresses.  Bra size changes during and after pregnancy, during and after breastfeeding, at menopause and with weight gains of 10 pounds or more. Remeasure for the best fit.

If you are having breast augmentation surgery, you will want to get a couple firm supportive athletic bras for the first 6 weeks or so.  6-10 weeks post-op measure for your new bra size as described above.  Avoid or remove underwire, but do go for a supportive fit.  Your breasts will make many changes over the first twelve months, so measure regularly and perform your molding compressions daily.  Typically they will settle in at 12 months post-op.  Also ask your physician if special precautions are needed for annual mammograms.