Step 1 of 3) What's your cup size?
The Original Camisole, Original Breeze, and Camisole Essentials fit cups DD through H (USA / Canada) , DD-FF (UK / AU) , E-H (EU)
The Breeze Essentials fits cups DDD-HH. (DDD = F cup)
Step 2 of 3) With a flexible measuring tape, measure around your ribcage directly up and UNDER your breasts, making sure there's no slack behind your back.
Step 3 of 3) Based on your ribcage measurement, choose the Size below that fits within the range of the Band Size.