Over 75 percent of women wear the wrong size bra, this could cause sagging breasts, shoulder and back pain, and other conditions. Bra Size Calculator helps you find out what size your bra is. Step 1: Measure your Band by wrapping a tape around your chest and back under neath your breast Step 2: Measure your Bust by wrapping a tape around your chest and back around the fullest area of your breast Step 3: Enter enter your measurement and click calculate You can pick the measurement unit between Inches and Centimetres Note: there are multiple ways to measure, so only use this App as a guide.