I think he is asking the actual equations, not the plug and play method.....
I did the same thing when i wanted to know my cfm, lbs/min, and a few other things. There are tons of calculators on the net, but I still like doing it by hand on paper as well. Search around, there are some really good books including "Maximum Boost". Buy, read it, know it.
I will be posting an excel file that will cover a lot of that math with a few pieces of plugged in information. May take me a few more days to get it better though.