Peak Flow Action-Plan Zones
Places a peak expiratory flow reading in the green, yellow or red zone of a written asthma action plan.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Current peak flow, L/min
- 300 L/min
- Personal best peak flow, L/min
- 500 L/min
Result: 300 of a personal best of 500 is 60 percent, the yellow zone
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Green
- 80 percent or more of personal best.
- Yellow
- 50 percent to below 80 percent of personal best.
- Red
- Below 50 percent of personal best.
- The reference
- The patient’s own personal best, not a predicted value. A predicted peak flow comes from a population equation and can be far from what a given person achieves when well.
- Establishing it
- While the patient is well and on treatment, over a period of measurement, and re-established periodically. A number from an exacerbation is not a personal best.
- What overrides it
- Symptoms. A meter cannot see accessory muscle use, speech in single words, or a silent chest, and severe symptoms in the green zone are still severe symptoms.
What you enter
- Current peak flow, L/min
- Personal best peak flow, L/min (not a predicted value)
- The personal best was established while the patient was well and on treatment
How this is calculated
National Asthma Education and Prevention Program. Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. NIH Publication No. 07-4051; 2007. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.