How To Use Your Peak Flowmeter

A peak flow meter is a small, plastic, tube-like device that measures how well air moves out of your lungs. Using the peak flow meter correctly will help you better monitor and manage your asthma.

Peak flow readings can warn you that your airways are narrowing, before you have symptoms.

Instructions for Use

  1. Stand or sit up straight
  2. Reset the indicator of the flow meter to 0 (zero)
  3. Hold the flow meter horizontally, making sure that your fingers do not block the opening
  4. Inhale as deeply as possible and place your mouth firmly around the mouthpiece making sure your lips form a tight seal
  5. Blow out as hard and fast as you can; the final position of the indicator is your peak flow number
  6. Reset the indicator to the bottom of the scale
  7. Repeat 2-3 times; write down the highest number, along with the date and time, in your peak flow diary

Personal Best Peak Flow Number

Your “personal best” peak flow number is the highest peak flow number you can reach over a two- to three-week period, when your asthma is under control. Monitor your peak flow numbers for your personal best:

  • At least twice a day for two to three weeks
  • When you wake up
  • Between noon and 2 p.m.
  • Before and after you take your quick-relief medication


Clean the flow meter at least every two weeks with warm, soapy water. Rinse well and allow to air dry.

: This material provides general information only. It should not be used in place of the advice, instructions, or treatment given by your doctor or other health care professional.