Yes, I tend to use liquid measuring cups for soup (even if it has chunks of veggies or meat in it) but if you want to calculate calories, you can calculate everything that went in then split it up by an x amount of servings.
For me, I feel that the calorie count would be somewhat more accurate if I use a digital scale to weigh everything in grams rather than dry/liquid measuring cups.
For example, instant brown rice- 43 grams dry (1/2 cup) is one serving equal to 1 cup cooked but when I tried to measure using a 1/2 (dry) measuring cup, it was actually closer to 60 grams and it wasn't even a heaping measurement. Hence me using the digital scale.
Since I take my soup and divide it into one cup portions to freeze, it's easy to count the number of portions.
You can weigh your soup (subtract weight for the pot) and figure out a serving that works for you.
I make my own soup in a separate pot (if I'm planning on feeding others). I count the calories in the whole thing and divide into storage containers. That way even if I'm off a bit on one bowl, it averages out as I eat the rest of them over time.
If it's canned soup I weigh it, it's easy to figure out with the lable and divide it (although I rarely eat only 1 serving, the whole can is usually only 200 or so calories).
If it's a soup I made, I weight the entire thing, then can divide it from there. I do that with any recipe I make that's like that (casserole, crock pot meals), anything that's a mishmash that you can't serarate the ingredients (like a chicken breast and a potato or something like that).
