Pack years are a way to measure how much the average person has smoked. You can calculate your pack years by multiplying the number of packs of cigarettes you smoke each day by the number of years you have smoked. For instance, if you have smoked one pack a day for 14 years, you have 14 pack years. A second example is that if you have smoked 2 packs a day for 20 years, you have 40 pack years. The calculation for this is 2 X 20 = 40 pack years. Health professionals use this information to assess your risk of developing various health conditions related to tobacco use such as lung cancer and chronic obstructive pulmonary disease (COPD). The fewer number of pack years you have, the lower your risk will be of developing smoking-related health problems

## How to calculate the pack years

A **pack year **is a way to measure how much the average person has smoked. It’s calculated by multiplying the number of packs of cigarettes smoked each day by the number of years that person has smoked.

## Example of pack year calculation

As an example, if you smoked 20 cigarettes a day for three years, your pack year would be 3. The average number of pack years in America is 20.

To calculate your pack years, multiply the number of packs of cigarettes you smoke each day by the number of years you have smoked. For example: if you smoked one pack per day for 10 years, your pack years would be equal to 10 (cigarettes) x 10 (years), or 5. Pack years are used to assess the risk of developing smoking-related health problems. The fewer pack years a person has, the lower their risk will be.

## Interpretation

Pack-year is a term used to measure how much the average person has smoked and is a way of estimating their risk of developing various health conditions related to tobacco use such as lung cancer and chronic obstructive pulmonary disease (COPD).

The lower your pack-years score, the better. A healthy adult who has never smoked or started smoking in adulthood would have a score of 0, while someone who has smoked 1.5 packs per day for 40 years would have a total pack year score of 120 (1 pack over 40 years = 20 packs/year x 40 years = 800 packs). A person with high blood pressure has an increased risk of stroke when compared to someone with normal blood pressure, so we can say that they are at greater risk for stroke than those without high blood pressure. These two factors together create what’s called relative risk:

If you have fewer pack years, the lower your risk will be of developing smoking-related health problems. If you have more pack-years, the higher your risk will be of developing smoking-related health problems.

Because we all want to live long lives, avoid cancer and heart disease and run marathons into our 70s (or older!), this is great news!

For more smoking-related calculations, you can use our Cigarette Calculator.

## FAQ

### How do you calculate a pack-year?

It is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked.

### What does a 40-pack-year mean?

Someone who has smoked 40 cigarettes (2 packs) daily for 20 years has a 40-pack-year history.

### What is the significance of pack years?

Pack years is a useful tool for assessing lung cancer risk, and it gives doctors a standard way to describe that risk in basic terms.