Passa Checked Collared setSize & Fit Guide Top MeasurementMeasure across the fullest part of the bust by threading a measuring tape across your back at band level and under each arm, being careful that your elbows are down and that the tape isn't pulled away from the body in the front. If the measurement falls on the half inch, round up. Waist MeasurementBend to one side to find natural indentation in torso. This is your natural waist. Run tape around natural waistline,