Lung Age Calculator / Smoking history
120 Pack Year Smoking History
Work out your smoking history in pack-years and check eligibility for lung cancer screening.
Your result
Enter your numbers and press the button. Your result appears here.
How pack-years are calculated
One pack-year is 20 cigarettes a day for a year.
Pack-years = (cigarettes per day ÷ 20) × years smoked
Example: 15 a day for 40 years = 0.75 × 40 = 30 pack-years.
20-point version
The 20-point Barthel scores each item 0–1, 0–2 or 0–3 and is the 100-point score divided by 5. Scores of 0–4 indicate very severe dependence.
Pack-year examples
| Smoking | 20 years | 30 years | 40 years |
|---|---|---|---|
| 10 a day | 10 | 15 | 20 |
| 20 a day | 20 | 30 | 40 |
| 40 a day | 40 | 60 | 80 |
Common questions
What does a high lung age mean?
Your FEV1 is lower than expected for your age and height, often because of smoking. Stopping smoking slows further loss.
Should I talk to a doctor?
Yes, if the result worries you or if you have new symptoms. These tools support, but do not replace, a clinical assessment.
Sources
- US Social Security Administration. Actuarial life table, 2022 period life table (2025 Trustees Report).
- Levine ME et al. An epigenetic biomarker of aging for lifespan and healthspan. Aging 2018;10:573–591; Liu Z et al. PLoS Med 2018;15:e1002718 (and correction).
- Morris JF, Temple W. Spirometric "lung age" estimation for motivating smoking cessation. Prev Med 1985;14:655–662. Quanjer PH et al. ECSC lung volumes and forced ventilatory flows. Eur Respir J 1993;6 Suppl 16:5–40.
- CDC. STEADI: Stay Independent brochure. Morse JM et al. A prospective study to identify the fall-prone patient. Soc Sci Med 1989;28:81–86.
- Bohannon RW, Andrews AW. Normal walking speed: a descriptive meta-analysis. Physiotherapy 2011;97:182–189. Studenski S et al. Gait speed and survival in older adults. JAMA 2011;305:50–58.
- Mahoney FI, Barthel DW. Functional evaluation: the Barthel Index. Md State Med J 1965;14:61–65. Shah S et al. J Clin Epidemiol 1989;42:703–709.
- Morley JE et al. A simple frailty questionnaire (FRAIL). J Nutr Health Aging 2012;16:601–608. Searle SD et al. A standard procedure for creating a frailty index. BMC Geriatr 2008;8:24.
- Kivipelto M et al. Risk score for the prediction of dementia risk in 20 years among middle aged people. Lancet Neurol 2006;5:735–741. Tombaugh TN, McIntyre NJ. J Am Geriatr Soc 1992;40:922–935.