To find the correct amount, you must consult your vehicle's owner's manual. The specifications will be listed there. Alternatively, you can look up the capacity using your VIN number on a parts website or a mechanic's database (like AllData or Mitchell 1, which are subscription services).
Trying to guess the amount of refrigerant could lead to overcharging or undercharging the system, both of which can damage the compressor and other components. It's crucial to use the correct amount specified for your specific vehicle.