The BodPod procedure involves a number of sequential measurements. The following are measured in order: the empty chamber, a 50 liter calibration cylinder, the subject (twice), and finally, a lung volume correction test. The empty chamber and 50 liter cylinder establish values used in calculating the subject's body volume.

All subjects must wear a swimsuit and swim cap during the BodPod test. This minimizes errors caused by air trapped in clothing and hair. Subjects are weighed prior to entering the BodPod, then sit comfortably in the measurement chamber. The door is closed and the run begins. Each subject run takes less than one minute. If the two subject measurements do not agree, a third run is done. The two closest runs are then averaged.

Once the body volume phase of the procedure is completed, the lung volume measurement begins. The subject remains seated in the BodPod, and is instructed to begin breathing normally through a disposable tube when given a cue. After 2 to 3 breaths, the tube airway is closed and the subject gently puffs against the closed airway (2 to 3 times, about once per second). Pressure in the breathing tube changes as the subject's diaphragm contracts and expands. Airway and chamber pressures are monitored and lung volume can be calculated. This completes the measurement procedure, and results for %fat and fat-free mass are displayed.

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