Find out what any appliance actually costs to run. Enter the device power in watts, how many hours a day you use it, and the price you pay per kilowatt-hour, and the calculator converts that into the energy used and the cost per hour, per day, per month and per year. This makes it easy to spot the quiet money-drains in a home, compare an old appliance against an efficient replacement, or check whether leaving something on standby is worth worrying about. Because you enter your own electricity price, it stays accurate for any tariff or country and needs no live data lookup. Multiply up across several devices to sanity-check a bill. All calculations run locally in your browser and nothing you enter is stored or sent.