Peak Flow Calculator: Monitor Your Lung Health & Asthma Zones

Calculate Your Peak Flow & Determine Your Zone

Your current reading from a peak flow meter.
Your highest reading when your asthma is well-controlled.

Your Peak Flow Results:

Your current PEF is

You are in the

Use our free Peak Flow Calculator to determine your Peak Expiratory Flow (PEF) and identify your asthma zones. Easily monitor lung function, track changes, and help manage respiratory conditions effectively. Input your personal best PEF, age, height, and gender for an accurate assessment of your respiratory health.

Formula:

The Peak Flow Calculator helps you understand your lung function by comparing your Measured Peak Expiratory Flow (PEF) against your Personal Best PEF. This comparison places your lung health into one of three zones:

  • Green Zone: Measured PEF is 80-100% of your Personal Best.
  • Yellow Zone: Measured PEF is 50-79% of your Personal Best.
  • Red Zone: Measured PEF is less than 50% of your Personal Best.

Where:

  • Measured PEF: Your current peak flow reading from a peak flow meter (L/min).
  • Personal Best PEF: The highest peak flow reading you've achieved when your asthma is well-controlled (L/min).

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