Pulmonary function tests are useful in evaluation of respiratory health of a person. Peak flow meter is the one of the simplest means of objectively assessing and monitoring the airway function. The normal peak expiratory flow rate (PEFR) is 400-600 L/min or 6-10 L/sec. PEFR increase in male till third decade and in females till second decade, and later decline with as age increases. Peak flow meter helps to regularly monitor and in self management of asthma.