No formula that I know of. When I'm figuring out one of my recipes, I make a list of the WW points in each ingredient so I have a total for the entire batch. Then when it's finished I measure how much there is, usually by putting it all into a large pyrex measuring bowl, and then figure out how many servings I can get for how many points. For instance, when I make chili, I figure the points for the entire amount of beans I put in, and the burger, etc. I measure it usually before cooking it all (but after browning the burger, onions). So if it's 6 cups, I can have have 1 cup for 1/6 of the points I figured, or 2 cups for 1/3 the points, etc. THis method works best on stuff like this, but if you have something less easy to measure, you can weigh it. I weigh the container empty first, then with food in it. Then I use the same method as above - 18 grams, I can have 3 gr for 1/6 the points, etc. HOpe this helps.
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