This can vary from system to system. You can usually get a good idea by looking at the information plate or sticker, which is located on your condensing unit where your model numbers are found. On the sticker/plate, you should find your refrigerant/freon type as well as the amount of freon (in oz.) your system should be charged with. This is not an exact amount because there are some other factors at play in determing the amount of charge, such as your copper line sets length and size.