Electricity cost calculator
Enter a device’s power, how long it runs and what you pay for electricity to see what it really costs to keep it on.
Settings
Include transfer fees and taxes for the most accurate result.
Running cost
- Per day of use
- $0.00
- Per month
- $0.00
- Energy per year
- $0.00
How the electricity cost is calculated
Energy use in kilowatt-hours (kWh) is the power in watts × hours of use ÷ 1,000. A 100 W TV used for 4 hours uses 0.4 kWh a day. Multiplying that by your electricity price per kWh gives the cost per day of use.
The yearly cost takes into account how many days a week the device runs, spread over the 365 days of the year. The monthly cost is a twelfth of the yearly cost.
You can find the power on the device’s rating label or in its manual. Many devices use less than their maximum power most of the time, so the result is an upper estimate. For the most accurate price, include transfer fees and taxes, not just the energy price.
Frequently asked questions
How do I calculate the electricity cost of a device?
Multiply the power in kilowatts by the hours of use and by the price per kWh. A 1,500 W heater running for 3 hours costs 1.5 kW × 3 h × $0.17 = $0.77 a day.
How many kWh does a device use?
Divide the wattage by 1,000 and multiply by the hours it runs. A 60 W laptop used 8 hours a day uses 0.48 kWh a day – about 175 kWh a year if it is used every day.
What electricity price should I use?
Use the total price per kWh from your electricity bill, including the energy price, delivery fees and taxes. Dividing the bill total by the kWh used gives a good average.
Does standby use electricity?
Yes, many devices draw a few watts on standby. Enter the standby power and 24 hours a day to see what it costs over a year.