I totally understand what you're saying. What I do is just add up all the calories in all of the ingredients and then divide by how many servings that I think it should make so that I have a good number of calories.
For instance say I'm making broccoli cheese rice:
Broccoli - 150 cal
Cheese - 300 cal
Rice - 450 cal
Total=900
If I want to make 8 servings I know that the cals in each serving will be 112.5 (900/8) or If I want each serving to be 150 I know that I've made enough for 6 servings (900/150)
Hope that made sense