Lena, I never go from the amount of water-liquid, so you can not guess with the thickness of the soup.
I go from the opposite, from the thick mass.
I cook the meat in a little water, for example 1-1.5 liters (depending on the amount of meat). Then I add vegetable sautéing, cabbage, potatoes (as an example). And only after that I add hot water, boiling water, to the desired consistency, the thickness of the soup, and bring the soup to readiness.
Boiling water in order not to stop the process of making the soup, so that the broth does not cool down from the addition of cold water, and it does not need to reheat from cold water. From the "shock" temperature drop of the broth, the broth may turn out to be tasteless, and some ingredients may even "become dull".
With this approach of determining the amount of water in the soup, the density will turn out to be the desired consistency, such as you need. And get exactly the number of servings that will be eaten without a trace. It is customary to consider the volume of a portion to be approximately 350-500 ml. ready-made soup for a person at one time.
