Bouillon granules can easily be substituted for the cubes in a recipe, you just need to have the conversion information. This is a guide about substituting bouillon cubes with bouillon granules.
If a recipe calls for chicken bouillon cubes and you only have granules, do you know how many cubes equals so many tablespoons of granules?
jho from Chassell
Usually you add 1 cube to make 1 cup of bullion. How many tsp of granules does it say on jar to make 1 cup of bullion? That would be the amount you use to substute for 1 cube.
Depending on the brand of granules (and the brand of cubes, for that matter), it's usually one teaspoon of granules to one cup of water. The directions are right on the jar's label, though, to be fair, they may be a bit small.
My experience is that one cube = one teaspoon.