Peak Flow Calculator

Free calculate peak expiratory flow rate (PEFR). This is an educational tool only - always consult a healthcare provider.

Patient Information

Optional: Enter measured value to compare with predicted

Results

Enter information to calculate peak flow

About Peak Flow

  • • Green Zone: 80-100% of predicted
  • • Yellow Zone: 50-79% of predicted
  • • Red Zone: <50% of predicted
  • • Used for asthma monitoring
  • • Best of 3 measurements