Step 1. Start by Measuring Under Your Bust
Begin by placing a measuring tape around your back and under your armpits. Bring the measuring tape around the front, just below the breast tissue. Make sure the measuring tape is snug around your body but not too tight. If you are in between sizes, round up or down to the nearest even number. This will be your under bust size (36, 38 etc.).
Step 2. Next, Measure Across Your Bust
Place the measuring tape around your back once again but this time measure around the fullest part of your breasts, over and across your nipples. Note your across bust measurement (B, C, etc.).