When determining the wattage for a microwave, you should go by the output wattage, which is the cooking power of the microwave. The output wattage is the amount of power that the microwave uses to cook or heat food.
The input wattage, on the other hand, refers to the power consumption of the microwave from the electrical outlet. It includes the power used by the microwave's internal components, such as the display, lights, and the magnetron (the device that generates microwaves for cooking).
The output wattage is the more relevant value when it comes to cooking times and efficiency. It directly affects how quickly and evenly your food will be cooked. Most microwave ovens will have a label that indicates the output wattage, typically ranging from 600 to 1200 watts or more. If you're comparing microwave ovens, make sure to look at the output wattage to determine their cooking power.