Calculating Pack-Years
Pack-Years is a very simple number to calculate: It is simply the number of packages of cigarettes smoked per day multiplied by the number of years you smoked. So here are the steps, and I'll give you some examples as well:
Figure out how many packages of cigarettes you smoke per day, based on a 20-cigarette package. This is best accomplished by dividing the number of cigarettes you smoke every day by 20.
Examples:
If you smoke 20 cigarettes per day, then the number is 20/20, or 1 package.
If you smoke 25 cigarettes, then the number is 25/20, or 1.25 packages.
If you smoke 43 cigarettes per day, then the number is 43/20, or 2.15 packages.
Now calculate how many years you have been smoking.
Examples:
If you have smoked for 5 years and 6 months, it is 5.5 years.
If you have smoked for 18 years, your number is 18.
If you have smoked for 20 years and 5 months, your number is 20-5/12, or about 20.42 years.
Finally, multiply packages by years to get pack-years.
Examples:
1 package multiplied by 5.5 years equals 5.5 pack years (1 x 5.5 = 5.5).
1.25 packages multiplied by 18 years equals 22.5 pack years (1.25 x 18 = 22.5).
2.15 packages multiplied by 20.42 years equals about 43.9 pack years (2.15 x 20.42 = ~ 43.9).
And there you have it. Pack-Years are just the number of packs smoked per day times the number of years you've been smoking them.
More about pack years
There is a lot of information out there about how many Pack-Years one has to smoke before one starts to get into serious health problems. The only number that seems to be quoted regularly is 20 Pack-Years as some sort of threshhold. If you have smoked more than 20 Pack-Years, you are at a much greater risk of something nasty or downright deadly getting you than if you have smoked less than 20 Pack-Years. Whether this is true or not is anybody's guess, of course, but that is a pretty common number, so I am personally more likely to believe it.
I did a simple Google search and came up with a lot of interesting articles.
But there are also a lot of good web sites for smokers trying to stop. Here's one I recommend.
This blog entry (Calculating Pack Years) is the most popular page on my entire web site. I presume most hits are from smokers wanting to find out their own personal number of pack years smoked.
If you want to learn how I quit smoking, I wrote a rather lengthy description of How I Quit Smoking. Because, after all, when I was a smoker I got really tired of hearing about why I should quit ... I just wanted to know how! :-)
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