A pack-year is a clinical quantification of cigarette smoking used to measure a person’s exposure to tobacco.
This concept is used to assess a person’s risk of developing lung cancer or other pathologies related to tobacco use.
Formula to calculate pack years.
![Calculate Pack Years.](https://www.learntocalculate.com/wp-content/uploads/2020/07/pack-years-1-1024x115.png)
Example:
Suppose a person smokes 1 pack of cigarettes everyday for 3 years. Calculate his pack years.
Since there are 20 cigarettes in a pack therefore;
![Calculate Pack Years.](https://www.learntocalculate.com/wp-content/uploads/2020/07/pack-years-2-1-1024x273.png)
Thus, the person’s pack years are 3.