Estimate smoking pack-years from cigarettes per day and years smoked.
| Pack-years | – |
Use this calculator for pack-years = (cigarettes per day ÷ 20) × years smoked. A pack is 20 sticks. Average the daily count if it changed over time; this page does not split eras. HSI adds time to first cigarette; that extra item is not here. Pack-years are an exposure sketch, not a lung-age clock.
Cigarettes / day: Average sticks per day.
Years smoked: Years at that average.
Pack-years: Cumulative pack-year exposure.
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