Knowing your correct bra size can mean the difference between a comfortable and supportive bra and one that fails to offer more than just basic support. The right fit in cup size, band size and the shoulder straps affects your comfort level, how your clothing fits, your shape and even your posture. Most department and lingerie stores offer free bra fittings, but if you're too embarrassed to have one done or are ordering online, measure yourself. Learn the correct method and buy the right bra.
Wear a soft bra without padding or a molded cup. Slip a cloth measuring tape around your back.
Bring the ends of the tape measure together to meet over your bust line. The tape measure should meet in the front across the top of your breasts, rather than underneath or directly around them. Write down the measurement that you get; this is your band length measurement. Round down to an even number if your measurement turns out to be an odd number.
Bring the ends of the measuring tape to meet over the fullest part of your breast, usually directly over the nipples. Write down this number; this is your bust size. Round up to the next whole number if this measurement falls on a half-inch size.
Find your cup size by subtracting the band size from the bust size. The difference corresponds with a letter. Generally, no difference or a half-inch difference means you're an AA. A 1-inch difference is an A, a 2-inch is a B, a 3-inch corresponds with a C, a 4-inch is a D. Women who record a 5-inch different wear a DD cup, and a 6-inch difference equals a DDD. Letters and numbers may vary slightly based on the manufacturer and bra style.
Try on a variety of bras to determine the best fit. Each manufacturer sizes its bras differently, and each stretches differently as well. What fits one person may not fit another person who measure the same size.