Bra Size Calculator Step 1: Take Your Measurements For best results, wear an unpadded bra or no bra. Use a soft measuring tape. Band Size (Underbust) in inches: (Measure directly under your breasts) Bust Size in inches: (Measure around the fullest part of your breasts) Your Calculated Bra Size: Size Chart Reference Band Size (inches) Cup Size Difference (inches) Cup Size Round to nearest even number: 28, 30, 32, 34, 36, 38, 40, 42, 44 1" A 2" B 3" C 4" D 5" DD/E 6" DDD/F 7" G 8" H Measuring Tips: Measure while wearing an unpadded bra or no bra Keep the measuring tape parallel to the ground Don't pull the tape too tight or leave it too loose Take measurements while standing straight Round measurements to the nearest half inch