Pick an appliance or enter its power in watts, say how long and how often you use it, and add your price per kWh. The calculator shows what it costs to run.
Results are estimates for planning. Check the figures before you make a financial or health decision.
How the Electricity cost of appliances works
Energy is measured in kilowatt-hours (kWh). One kWh is one kilowatt, or 1,000 watts, used for one hour. The calculation is:
cost = watts ÷ 1,000 × hours × price per kWh
From your inputs the tool works out:
- Energy per day = watts ÷ 1,000 × hours per day.
- Energy per year = daily energy × days per week ÷ 7 × 365.
- Running cost per year, month (a twelfth), week (a fifty-second), per use and per hour.
You can choose a preset such as a kettle, air fryer or washing machine, which fills in a typical wattage, or choose custom and type your own. The price per kWh is your own tariff, found on your bill or in your supplier’s app. The tool does not supply a price.
Limits: heating appliances only draw full power while heating, so a fridge or oven used at full wattage all the time will overstate its cost. Standing charges are not included, and preset powers are typical figures, not exact ones.
Worked example
Using the default values in the calculator above:
| Input | Value |
|---|---|
| Appliance | Kettle |
| Power | 3000 watts |
| Hours used each day | 0.25 hours |
| Days used each week | 7 |
| Electricity price per kWh | £0.26 |
Running cost per year: £71.18
| Energy used per year | 273.8 kWh |
|---|---|
| Cost per month | £5.93 |
| Cost per week | £1.37 |
| Cost per use | £0.20 |
| Cost per hour | £0.78 |
Tips and common mistakes
Check the wattage on the appliance label or in the manual, since models vary widely. For thermostat-controlled devices such as ovens and heaters, enter the average hours of actual heating rather than the time switched on.
Use the unit rate from your own bill, and update it if your tariff changes. If the cost per hour surprises you, compare appliances by their cost per use, such as a kettle boil against a microwave. For the full picture, add up the main appliances over a year. Plug-in energy monitors can give a measured figure.
Frequently asked questions
What is a kWh?
A kilowatt-hour is the energy used by a 1,000-watt appliance running for one hour. It is the unit your electricity bill is based on.
Where do I find my price per kWh?
It is on your bill, in your supplier’s app or on your tariff details. This tool does not supply a price, as it depends on your tariff.
Why might my real cost be lower than the result?
Many appliances, such as ovens and fridges, cycle on and off, so they do not draw full power all the time. Enter the real average running time if you can.