Peak flow meters

Three types of peak flow meters, showing mouthpiece and numbered scale on each.

A peak flow meter is a pocket-size device that measures peak expiratory flow (PEF), or how much air a person can quickly breathe out. To measure PEF, the person takes a deep breath and then blows into a tube on the peak flow meter as hard and as fast as possible. A scale on the device shows how much air is breathed out. This can be done at home.

Peak flow meters come in many shapes and sizes.

This information does not replace the advice of a doctor. Healthwise, Incorporated, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content.

© 1995-2021 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.