Appliance Electricity Cost Calculator
Find out what any appliance costs to run: enter its wattage, how many hours a day you use it and your price per kWh, and get the cost per hour, per day, for any number of days and per year. It assumes the appliance draws its full rated power the whole time, so for fridges, heaters and other thermostat-controlled appliances, read the tips first.
Appliance and tariff
10 minutes = 0.17 h, 30 minutes = 0.5 h.
30 for a month, 365 for a year, 120 for a season.
Take it from your electricity bill. The default is an illustrative US average, not your rate.
Before you trust the number
- Use the wattage from the appliance's rating plate or manual. If only amps are listed, multiply amps by your mains voltage (120 V in the US, 230 V in the UK and EU) for a rough figure.
- Fridges, freezers, heaters, air conditioners and ovens cycle on and off, so the rated wattage overstates their real use. If the appliance has an energy label with kWh per year, that figure is more reliable. For a fridge, a common rule of thumb from US extension guides is to count only a third of the time it's plugged in. A plug-in power meter gives the real number.
- Running several identical devices, like four bulbs? Add their wattages together and enter the total.
- Short runs count too: 10 minutes is 0.17 hours, 30 minutes is 0.5. A 2,000 W kettle used for 10 minutes a day costs about as much as a 50 W device left on for 7 hours.
How this is calculated
Electrical energy is power times time. The appliance's wattage divided by 1,000 gives kilowatts; multiplied by the hours it runs, that's the kilowatt-hours (kWh) your meter counts. Multiplying the kWh by your price per kWh gives the cost. This calculator does that for one hour, one day, the number of days you choose, and a full year of daily use (365 days). It's the same method used in US Cooperative Extension energy guides, UK energy-advice leaflets and introductory physics textbooks. The result is only as good as the inputs: it assumes the full rated power for every hour you enter and one flat price per kWh.
Frequently asked questions
Which price per kWh should I enter?
The unit rate from your electricity bill, the price per kWh, not the total bill divided by anything. If you have day and night rates, enter the rate for when the appliance actually runs. Fixed daily or monthly charges (standing charge, customer charge) don't depend on how much you use, so they're not part of an appliance's running cost. The default of $0.18 is roughly the 2026 US residential average from the EIA, not your rate.
Why is my real bill different from what this shows?
Usually because the appliance doesn't draw its full rated power all the time. Thermostats and compressors switch it on and off, and many devices draw less than the label maximum. Tiered tariffs, taxes and fixed charges also change the bill. For a precise figure, measure the device with a plug-in power meter and enter the measured wattage.
Is there a calculator for specific appliances?
For a 3D printer, the filament cost calculator adds filament and printer wear to the electricity. For an air fryer, this tool gives the running cost; the air fryer conversion calculator tells you the time and temperature to use. EV charging has its own losses and per-mile maths, so it isn't covered here.
Part of Home Improvement Calculators