Jillian Sizing Chart
Measure the fullest part of your chest, relaxed. Ensure the tape is in a straight even line across your chest and back.
Have you arms at your side for the best measurement.
Measure the smallest part of your torso. Usually you would find this is between your ribcage and belly button.
Measure around the fullest part of your hips and buttocks, ensuring the tape is as level as possible.