I just built a simple spreadsheet with some formulas.
Basically goes like so:
-Add the total oz. of all the ingredients used
-Enter nutritional stats per serving, then multiply by total # of servings per container/package
-Total each stat (i.e.: all ingredients in pan = XXX Calories, etc...)
-Weigh out your serving size in oz.
-Calculate your serving as % of total weight in oz.
-Multiply nutritional stats by your serving size %
I think it's pretty accurate. I'm happy to e-mail my example...I made a simple ground beef and canned veggie dish to test it.
(cool...was able to zip and attach it)