Inspiratory reserve volume (IRV) 

Expiratory reserve volume (ERV)

1. It is the maximum volume of air that can be inhaled after a normal inspiration. 

2. It is about 2500 – 3500 mL in the human lungs.

1. It is the maximum volume of air that can be exhaled after a normal expiration. 

2. It is about 1000 – 1100 mL in the human lungs. 

Inspiratory capacity (IC) 

Expiratory capacity (EC)

1. It is the volume of air that can be inhaled after a normal expiration. 

2. It includes tidal volume and inspiratory reserve volume. IC = TV + IRV 

1. It is the volume of air that can be exhaled after a normal inspiration. 

2. It includes tidal volume and expiratory reserve volume. EC = TV + ERV

Vital capacity (VC) 

Total lung capacity (TLC) 

1. It is the maximum volume of air that can be exhaled after a maximum inspiration. It includes IC and ERV. 

2. It is about 4000 mL in the human lungs.

1. It is the volume of air in the lungs after a maximum inspiration. It includes IC, ERV, and residual volume. 

2. It is about 5000 – 6000 mL in the human lungs.