Appliance running cost calculator
Enter an appliance's wattage and daily use to get kWh and running cost per hour, day, month and year, using current US, UK or European electricity prices or your own rate.
- Per hour of use
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- Per day
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- Per month
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- Annual consumption
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Results are indicative estimates based on the values you enter. Always check your appliance labels, your tariff and the manufacturer’s data.
- Formula: kWh = watts × hours ÷ 1,000, then cost = kWh × your price per kWh.
- At the US average residential price of 18.31¢/kWh (EIA, July 2026), a 1,500 W heater costs about 27¢ per hour at full power.
- Under the UK price cap (26.32p/kWh, Oct–Dec 2026, Direct Debit average), 1 kW for one hour costs about 26p.
- For thermostat-controlled appliances, set the share of time they actually run.
How to use the calculator
- Wattage: find it on the appliance’s rating plate (usually underneath or on the back) or in the manual. If you know the annual consumption from an energy label, type it in the “known annual consumption” box instead.
- Hours per day: how long the appliance is switched on. A kettle that boils for 3 minutes is 0.05 hours.
- Share of time at full power: leave 100% for appliances that always draw their full rating (kettle, light bulb). Heaters and air conditioners with a thermostat cycle on and off; only a measurement (a plug-in energy monitor or your smart meter) tells you the real figure.
- Tariff: pick a reference price (US average, UK price cap, Eurostat country averages) or type the unit rate from your own bill.
The formula
Energy is measured in kilowatt-hours (kWh). A 1,000 W (1 kW) appliance running for one hour uses 1 kWh.
Energy (kWh) = watts × hours × share of time at full power ÷ 1,000 Cost = kWh × price per kWh
Example: a 1,500 W space heater running 8 hours a day at full power uses 12 kWh a day. At 18.31¢/kWh that is about $2.20 a day, or roughly $66 for 30 days.
Reference prices used
| Market | Price per kWh | Source and period |
|---|---|---|
| United States (average residential) | 18.31¢ | EIA, July 2026 |
| United Kingdom (price cap, Direct Debit average) | 26.32p | Ofgem, 1 Oct–31 Dec 2026 (no VAT on electricity in this period) |
| France (EDF regulated tariff, Base) | €0.2001 | EDF, from 1 Aug 2026 |
| EU countries | varies | Eurostat, latest complete half-year |
US prices vary a lot by state, and UK prices vary by region and payment method, so your own bill is always the best figure to use. See our table of electricity prices in Europe.
Reading an energy label
Labels show consumption differently depending on the product:
- Fridges and freezers (EU/UK label): kWh per year.
- Washing machines and dishwashers (EU/UK label): kWh per 100 cycles of the eco programme; divide by 100 and multiply by your cycles per year.
- TVs (EU/UK label): kWh per 1,000 hours of use.
- US EnergyGuide label: estimated yearly electricity use in kWh and an estimated yearly operating cost at a stated price.
Why your bill won’t match exactly
The calculator estimates the cost of the energy used. Your bill also includes a standing charge (a fixed daily or monthly fee), and on time-of-use tariffs the price changes during the day. Compare real-world measured consumption for dozens of appliances on our page how much electricity appliances really use.