BBQ Ratio Calculator



Based on smoker ratios developed by Alien BBQ and posted at



I produced these files to help fellow pit builders calculate their pit ratios. When I was building my first smoker I came across Alien BBQs ratios on the Smoke Ring just in time. Without a doubt the ratios Mike posted kept me from making costly mistakes on my first build. Thanks Mike!


As I was building the smoker I first made a crude spreadsheet to help me make sure I was calculating correctly. I soon found that it also helped me quickly recalculate as needed during the modification periods. The sheets below grew out of that first sheet.


UPDATED 8-2009

I have replaced the original calculator with two new ones. These files separate calculations for a Circular firebox and square firebox. Both also allow you to enter your cooking chamber size to calculate your firebox size based on the 1/3 rule of thumb. Both files are Excel files. At this time I can only offer them in this format.


I hope that these new files will be easier for builders to users. Feedback is appreciated!


Thanks To K.A.M. for his suggestions on improving the files.



To access the file:


1.  Choose which type of firebox you want and click on one of the links below.

2.  You will be asked if you want to save or open the file. If you open the file you will not be able to save the changes. If you download the file you can save your information and go back to it as needed.

3.  Once you have the calculator you want open, just follow the instructions (I hope they are clear).


Download here:


Circular firebox calculator


Square firebox calculator



Good luck with your smoker and dont forget to post pictures!


Tom C.