Free Healthcare Tool
Smoking Pack-Year Calculator
Summarize cigarette exposure across one or two smoking periods.
What this answers:
- What is my total pack-years of cigarette exposure across one or more periods of different smoking habits?
A pack-year is a standardized exposure summary, not a risk score. It does not by itself determine cancer risk or screening/coverage eligibility, and this tool does not convert vaping or cigars using an invented equivalence.
Total exposure
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How it's calculated
pack-years = ∑ (cigarettes/day ÷ 20) × years
Worked example
20/day for 10 years, then 10/day for 10 years: (20/20)×10 + (10/20)×10 = 15 pack-years.
Source: American Cancer Society, Lung Cancer Screening Guidelines (pack-year definition). Source last checked September 28, 2026.
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