There is no one definitive answer to this question. Ghee and butter are both dairy products, and so their ratios will depend on the recipe you are using them in, as well as your own preferences. Generally speaking, though, you can use about 1/2 as much ghee as butter in a recipe. So if a recipe calls for 1/4 cup of butter, you would use only 1/8 cup of ghee. Experiment a little to find what works best for you!