https://docs.google.com/open?id=0B1XuU3 ... m45Q29YLTQ
this is a spreadsheet of some brewing calculations from a zymurgy article, "brew by the numbers." i've found it particularly useful for getting good carb volumes when bottling. you should be able to just download and play around with it. pretty simply plug in your numbers in the bordered cells and the calcs pop up in the colored cells.
you can download the article free from the aha site.
fist