The Lean Body Sports Bra
Measure a perfect fit, take your measurements with a flexible tape measure while wearing no clothing or only undergarments.
Horizontally wrap the tape around the fullest part of your chest along your nipple line and across the shoulder blades.
Horizontally wrap the tape around the smallest part of your waist which is just above the navel.
Stand with your feet together and horizontally measure around the fullest part of your hips including the largest part of your butt.