Normal Peak Expiratory Flow Range: Charts & Zones

Peak expiratory flow (PEF), or peak flow, measures how quickly you can exhale air from your lungs. It’s a simple home test using a handheld peak flow meter — crucial for managing asthma, COPD, or other lung issues.

Peak Expiratory Flow (PEF) Guide 2026

Maximum exhalation speed (L/min). Use your personal best when lungs are well-controlled.

GREEN ZONE

80–100% of personal best

All clear — well-controlled
Continue regular treatment

YELLOW ZONE

50–80% of personal best

Caution — airways narrowing
Use quick-relief medicine + action plan

RED ZONE

<50% of personal best

Medical alert — severe issue
Rescue medicine NOW + emergency care

Adults — Typical Ranges (L/min)

Men: 400–700+ (avg 500–650)
Women: 300–500+ (avg 350–500)

Drops ~5–10 L/min per decade after 30–40

Children — By Height (approx. L/min)

Height (inches)	PEF (L/min)
43–50	150–240
51–55	250–300
56–60	300–380
61–65	380–450+

Based on American Lung Association (updated Jan 2026), NHLBI, Cleveland Clinic. Zones use personal best (highest stable reading). Consult doctor for your values.

A single “normal” PEF number doesn’t exist for everyone. It varies by age, height, sex, and sometimes ethnicity. The two main references are:

Predicted values — averages from healthy population studies.
Personal best — your highest reliable reading when lungs are healthy and controlled (this is the gold standard for daily use).

Why Peak Flow Monitoring Matters

Daily PEF checks help:

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Spot airway narrowing early, often before symptoms worsen.
Track asthma control and adjust meds.
Follow your Asthma Action Plan (per NHLBI guidelines).
Identify triggers like allergens, exercise, or pollution.

American Lung Association: Measuring Your Peak Flow Rate (updated January 15, 2026)

Information verified by the iythealth.com team.

Normal PEF Ranges for Adults

Typical ranges for healthy adults (liters per minute, L/min):

Men: 400–700+ L/min (often 500–650 for average height/age).
Women: 300–500+ L/min (often 350–500).

PEF drops ~5–10 L/min per decade after 30–40. Taller/younger people have higher values.

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Predicted Average PEF Values for Adults (Approximate, Caucasian, based on NHLBI/UNC charts)

Age (years)	Height 60–65″ (152–165 cm)	Height 65–70″ (165–178 cm)	Height 70–75″ (178–190 cm)	Men (L/min)	Women (L/min)
20–30	Lower	Average	Higher	550–650	400–500
30–40	Lower	Average	Higher	530–620	380–480
40–50	Lower	Average	Higher	510–600	360–460
50–60	Lower	Average	Higher	480–570	340–440
60+	Lower	Average	Higher	450–550	320–420

Note: These are averages; actual “normal” can vary ±100 L/min for men, ±85 L/min for women. Use tools like MDCalc Estimated Peak Expiratory Flow for personalized prediction.

Cleveland Clinic: Peak Flow Meter

Normal PEF Ranges for Children

Height matters most (not age until teens). Use low-range meters for young kids.

Approximate Predicted PEF for Children (L/min)

Height (inches)	Height (cm) Approx.	Predicted PEF (L/min)
43–50	109–127	150–240
51–55	130–140	250–300
56–60	142–152	300–380
61–65	155–165	380–450+

Re-check personal best as kids grow.

The Traffic Light Zones: Green, Yellow, Red

Zones are based on your personal best (not predicted averages), using the American Lung Association / NHLBI system:

Green Zone (80–100% of personal best): All clear — lungs well-controlled. Continue regular meds.

Yellow Zone (50–80% of personal best): Caution — airways narrowing. Take quick-relief inhaler, follow action plan, call doctor if needed.
Red Zone (<50% of personal best): Medical alert — severe issue. Use rescue medicine now, seek emergency care (911/ER).

Example (personal best 500 L/min):