Pack-Year Calculator - Smoking History & Lung Screening Criteria
Pack-Year Calculator
Measure your smoking history in pack-years
Pack-Years Made Simple
Pack-years = packs per day × years smoked. Smoking 20 cigarettes a day for 10 years is 10 pack-years.
Several Periods
If your habit changed over the years, add each period separately and they are summed.
Screening Criteria
Optionally check the 2021 US Preventive Services Task Force criteria for annual low-dose CT lung screening.
Full Privacy
Everything is calculated in your browser.
Why Doctors Ask About Pack-Years
Pack-years combine how much and how long you smoked into one number, because risk of lung cancer, COPD and heart disease rises with the total exposure. It is used in clinical histories and to decide who should be offered screening. In the United States, the 2021 USPSTF recommendation covers adults aged 50 to 80 with at least a 20 pack-year history who currently smoke or quit within the past 15 years.
This is general information, not medical advice. Screening guidance differs between countries and changes over time, and your doctor also considers other risks. Whatever the number, quitting smoking lowers your risk, and free help is available from health services. If you have symptoms such as a lasting cough, coughing blood or unexplained weight loss, see a doctor promptly.
Key Takeaways
- Multiple periods: Add as many smoking periods as you need.
- Clear reasons: If you do not meet the screening criteria, the calculator says which one.
- Information only: Not a diagnosis or medical advice.