Learn your size. Women too often buy bras that don’t truly fit. But “don’t assume that department-store salespeople will measure you correctly.” Either seek help at a lingerie specialist or learn to measure yourself.
Prioritize band width. “All the support comes from the band,” so take two measurements to get that size right. First, “tightly wrap a tape measure around your ribs, directly under your breasts.” Next, wrap the tape around your back, under your arms, and across the top of your breasts. If the measurements differ, use the average.
Cup size next. Now place the tape on your sternum, between the breasts, “and extend it over the widest part of the breast to the point where it connects with your rib cage.” Four inches is roughly an A cup, five inches a B, and so on. That said, bras vary in size by brand, so “you really have to try them on.”