Appliance electricity cost calculator

What this calculates

Cost is watts ÷ 1,000 × hours × your rate. That is the same arithmetic your utility uses — no hidden multipliers, no "peak hour" guesses. Every figure updates as you type.

Getting the watts right

Check the label on the back or bottom of the appliance, or the power brick. If it lists amps only, multiply amps × volts (120 in the US) to get watts. If it lists a range, use the higher number for a worst case.

Getting the hours right

This is where estimates go wrong. A refrigerator does not "run 24 hours" at its label wattage — enter its running watts and about 8 hours, which approximates the compressor duty cycle. A TV on for four hours means four hours. A device that idles all day (router, set-top box) is 24 hours at its standby draw, not its active draw.

Finding your electricity rate

Divide the total dollar amount on your last bill by the kWh used. That blended number is far more useful than the headline rate, because it folds in distribution charges, taxes and fees. US residential average sits near 16.5¢/kWh, ranging from about 11¢ to 30¢ by state.