The easiest way to determine the wattage an appliance is running at is to multiply the amperes by the volts. This applies to most appliances.However, large appliances with motors, such as refrigerators and air conditioners, require additional power to start. This surge is also called cranking wattage and is typically 1-2 times the operating wattage of the device.You can usually find wattage information directly on the device itself or in the user manual.