The average total lung capacity of an adult is between 4 and 6 liters, according to Family Practice Notebook. Total lung capacity can be subdivided into vital capacity and residual volume.
Total lung capacity is the volume of air in the lungs at the end of maximal inspiration. Vital capacity is the maximal volume expelled after maximum inspiration. Residual volume is the volume of air remaining in the lungs after maximal expiration. Residual volume is between 1 and 2.4 liters in an adult, while tidal volume, the volume inspired and expired with each normal breath, is normally 6 to 7 milliliters per kilogram of body weight.