Pack Years Calculator
Calculate pack years, a measure of cumulative smoking exposure used to assess risk of lung cancer and other diseases.
Published by:
isCalculator Editorial Team
Was this calculator helpful?
How to use this tool?
How to Use the Pack Years Calculator
- Enter Cigarettes per Day: Input the average number of cigarettes you smoke each day. This must be a whole number (e.g., 20).
- Enter Years Smoked: Input the total number of years you have smoked. You can use decimals for partial years (e.g., 10.5).
- Click "Calculate Pack Years": Press the button to compute your result.
- Read the Result: The calculator displays your pack years, rounded to two decimal places. A pack year equals smoking 20 cigarettes per day for one year. Higher values indicate greater smoking exposure.
Note: All inputs must be zero or positive. Cigarettes per day must be a whole number. The formula used is: Pack Years = (Cigarettes per Day ÷ 20) × Years Smoked.
Previous Results
| Result | Inputs | Date |
|---|
Frequently Asked Questions
A pack year is a unit for measuring the amount a person has smoked over time. It is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked.
Pack years = (Cigarettes per day ÷ 20) × Years smoked. For example, smoking 20 cigarettes per day for 10 years equals 10 pack years.
Pack years are used by healthcare providers to estimate a person's risk of developing lung cancer, COPD, and other smoking-related diseases. A higher pack year number indicates greater exposure and risk.
Generally, 30 pack years or more is considered high risk, especially for lung cancer screening. However, any smoking increases risk, and lower pack years still carry health concerns.
