Electricity cost calculator
The running cost of any appliance from its wattage and hours of use.
Cost per month
Rounded for displayCost per month: ≈ 3.80
- Cost per day
- ≈ 0.13
- Cost per year
- ≈ 45.63
- Energy per day
- 0.500 kWh
- Energy per year
- 182.5 kWh
How it works
Energy is power multiplied by time. A device drawing 1,000 watts for one hour uses 1 kilowatt-hour (kWh), the unit on your bill.
The daily energy is multiplied by your price per kWh. A month is taken as one twelfth of a 365-day year.
Standby power, standing charges and time-of-use tariffs are not included. Results are in the currency of the price you enter.
Formula
kWh per day = watts × devices × hours ÷ 1000 Cost per day = kWh per day × price Per month = per day × 365 ÷ 12; per year = per day × 365
Worked example
A 100 W device used 5 hours a day uses 100 × 5 ÷ 1000 = 0.5 kWh. At 0.25 per kWh that is 0.125 a day, 3.80 a month and 45.63 a year.
Questions people ask
How many watts is a kilowatt-hour?
A kilowatt-hour is energy, not power: 1,000 watts used for one hour, or 100 watts for ten hours.
Where do I find my price per kWh?
On your electricity bill or your supplier’s tariff page, usually as the unit rate.