Appliance Wattage Calculator

Find an appliance's power draw from its amps and voltage.

How the Math Works

The Appliance Wattage Calculator uses the fundamental electrical power formula: watts equals amps multiplied by volts. This relationship, P = V x I, represents how electrical power is calculated in any direct current circuit. When you know the current (amps) flowing through an appliance and the voltage of the power source, multiplying these two values gives you the power consumption in watts, which is the standard unit of electrical energy. The formula works because power measures the rate of energy transfer, and it's directly proportional to both the current flowing and the electrical potential that drives it.

Practical Applications

To use this calculator practically, simply enter the amperage rating of your appliance and the voltage of your power source. For household appliances, you'll typically use 120 volts in North America or 220-240 volts in many other countries. Once you input these values, the calculator instantly shows the wattage. This is especially useful when comparing appliances, planning electrical loads, or selecting appropriate power strips and extension cords that can handle the required amperage safely.

Day-to-Day Use

Understanding your appliance wattage helps you save money and energy in daily life. By calculating how much power each device uses, you can identify energy hogs and make informed decisions about replacements or usage patterns. This knowledge helps you size batteries for backup power, choose appropriate circuit breakers, and avoid overloading outlets when hosting guests with multiple devices. Additionally, knowing wattage helps you budget for electricity costs, as your utility bill directly correlates with your total energy consumption in watt-hours or kilowatt-hours.

Worked example

5 A × 120 V → 600 W.

FAQ