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Glossary Health & Fitness

Pack-year

A pack-year is a measure of smoking exposure: the number of packs of 20 cigarettes smoked per day multiplied by the number of years smoked.

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In more detail

One pack a day for 20 years, or two packs for 10, is 20 pack-years. Guidelines for lung-cancer screening use pack-years together with age and time since quitting.

Try these tools

Pack-Year Calculator

Calculate pack-years from cigarettes per day and years smoked, across one or several periods.

See also

  • Glossary GFR (glomerular filtration rate)
    GFR is the volume of blood the kidneys filter per minute, estimated from a creatinine blood test, age and sex.
  • Cheat sheet Medical Formulas Cheat Sheet
    A1C to glucose, blood pressure bands, cholesterol, kidney function, QTc, blood alcohol and IV drip rate with worked examples.
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