Not your bra size! Take the tape around your back and bring it across the fullest part of your bust. Your arms should be relaxed, down at your sides. You must wear bra when taking this measurement.
Waist
This is the smallest part of your waist. Typically it's an inch or so above your belly button. Also known as the natural waistline.
Hips
This is the widest part of your hips, across the hipbone. Measurement is taken approximately 7 inches below the natural waistline. This measurement is not needed for full gowns.