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Lungs: Biological Lung-Age and PEF Estimator

Medically-inspired "Lung Age" calculator using the Morris and Temple formula. Compares your measured Peak Expiratory Flow (PEF) against predicted values for your age, height, and sex to estimate the biological age of your lungs.

Enter Values

Biological Sex

Chronological Age

Height (cm)

Measured Peak Flow (L/min)

Smoking Status

Result

Enter values above and click Calculate to see your result.

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Our AI assistant provides general estimates and advice only. Please consult a qualified healthcare professional before making any health-related decisions.

Formula

Core Formula

\text{Lung Age} = \frac{k_1 \cdot \text{Height} - k_2 - \text{FEV}_1}{k_3}

How it works: The calculator estimates Lung Age using the Morris and Temple (1985) reference values. Since home users measure Peak Flow (PEF), we use a validated proxy ($FEV_1 = PEF / 100$) to calculate the volume-based lung age.

Review and Methodology

Updated Apr 10, 2026

This calculator runs locally in your browser. Inputs are converted into the units required by the formula, and the result is paired with supporting references so you can verify the method before using it for planning or estimates.

Worked Example

A 45-year-old male, 180 cm tall, with a PEF of 450 L/min:

1. Predicted PEF (Morris 1988): 10.02 L/sec (approx 601 L/min).

2. Estimated FEV1: 450 / 100 = 4.50 L.

3. Lung Age (Male): (0.0362 * 180 - 1.26 - 4.50) / 0.032 = 23.6 years.

Result: This user has the lung capacity of a 24-year-old.

What Is Your Biological Lung Age?

Lung age is a concept introduced to help people understand their respiratory health in relatable terms. Instead of looking at complex flow-volume loops, "Lung Age" tells you how old your lungs are compared to a healthy non-smoker of the same height and sex. It was originally developed as a motivational tool to help smokers quit by visualizing the damage or maturity of their lungs.

Reference Standard: We use the Morris and Temple equations, which are the clinical gold standard for lung age modeling.
Peak Flow (PEF): This measures how fast you can blow air out of your lungs. It is a key indicator of airway health and lung elasticity.
The FEV1 Proxy: While clinical tests use "Forced Expiratory Volume" (FEV1), home peak flow meters provide a highly correlated proxy ($PEF / 100$) used in many screening tools.
Biological Aging: Factors like smoking, air pollution exposure, and lack of cardiovascular exercise can "age" your lungs faster than your calendar years.

This tool is for educational purposes. If your lung age is significantly higher than your actual age, or if you have frequent shortness of breath, please consult a medical professional for a formal spirometry test.

You can also calculate changes using our BMI Calculator or Corrected Age Calculator.

Estimated Normal Peak Flow Range (L/min)

Typical average Peak Flow values based on age and height for healthy non-smokers (Morris 1988).

Height (cm)	20 Years	40 Years	60 Years
160 cm (Female)	440 - 480	420 - 460	400 - 440
175 cm (Male)	580 - 640	560 - 620	540 - 600
190 cm (Male)	680 - 740	660 - 720	640 - 700

Note: Values are estimates. "Normal" ranges vary significantly by individual fitness and ethnicity.

Frequently Asked Questions

What is a "good" lung age?

Ideally, your lung age should be equal to or less than your chronological age. If your lung age is lower than your actual age, it indicates excellent respiratory capacity, common in athletes.

Why does height matter for lung age?

Taller people naturally have larger thoracic cavities and, therefore, larger lung volumes. Lung age formulas must adjust for height to avoid penalizing shorter individuals or overestimating the health of taller ones.

How can I lower my lung age?

You cannot "reverse" lung tissue damage, but you can improve efficiency. Quitting smoking is the number one factor. Regular aerobic exercise (running, swimming, cycling) improves the strength of respiratory muscles, and avoiding indoor/outdoor pollutants protects existing function.

Is Peak Flow the same as Lung Capacity?

Not exactly. Peak Flow (PEF) measures the speed of expiration (flow), while capacity usually refers to volume (FVC/FEV1). However, flow rate is a very strong indicator of how well your airways are performing.

Can vaping affect my lung age?

Yes. While different from traditional smoking, vaping can cause inflammation in the small airways (bronchiolitis), which can restrict flow and increase your estimated biological lung age.

How can I put this Lungs: Biological Lung-Age and PEF Estimator on my blog or website?

Yes, the Lungs: Biological Lung-Age and PEF Estimator is fully embeddable. Tap "Embed" above to configure appearance and copy the code. It is free to use, works on any platform (HTML, WordPress, CMS), and adjusts to any screen size automatically. Visit calculory.com/services/embed-calculators for the complete guide.

Medical Disclaimer

This calculator is provided for informational and educational purposes only. It is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any decisions based on these results. Do not disregard or delay seeking medical advice because of information obtained from this tool.

AI Assistant

Ask about this calculator

I can help you understand the lungs: biological lung-age and pef estimator formula, interpret your results, and answer follow-up questions.

Try asking

Our AI assistant provides general estimates and advice only. Please consult a qualified healthcare professional before making any health-related decisions.

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