When measuring to determine your bra size you should, if possible, wear a comfortable standard underwired bra (not padded or push-up, etc.) You should remain in a standing position, keep your back and shoulders comfortably straight (don't hold your breath or push your chest out). Be relaxed. It can be difficult to measure yourself so you may have to ask a friend to help you, this will enable you to stand in the perfect position for measuring and allow you to keep your arms down by your sides.
Use a soft tape measure. To obtain your band size measurement, measure very snugly around your rib cage, just underneath your breasts. It should feel tight. Be sure that the tape measure lies straight all the way around. Enter this figure in the pink Below field (1). This measurement can be in inches or centimeters.
Measure loosely around the fullest part of your bust (usually over the nipples), keeping the tape measure straight all the way around your body. Enter this figure in the blue Bust field (2). This measurement can be in inches or centimeters but must be the same as in step 1.
Measure snugly around your rib cage above your breasts and under your arms kepping the tape measure level all the way around. Enter this figure in the green Above field (3). This measurement can be in inches or centimeters but must be the same as in steps 1 & 2. note: This third measurement is optional. If you leave this field empty, your bra size will be calculated using only the first two measurements, however, in order to obtain the most accurate results you are recomended to use all three measurements.