If a recipe calls for two 10.5 oz cans of broth and 2 cans of water and you have two cans of 14oz how much water should you use if you don't want to add two 14oz cans because it might be too watery?

So you need 21 oz of broth and 21 oz of water. Add the 14 oz can first, then you need an additional 7 oz. 7 oz is one half of the 14 oz can. So you just add a half of can of the one you have left over. In a nutshell you need 1 1/2 - 14 oz cans to make you recipe.