Electricity Cost Calculator - Free Online Tool
Estimate appliance electricity use and running cost.
About this tool
Estimate an appliance's energy use in kilowatt-hours (kWh) and its variable electricity cost from the wall power draw, hours used per day, number of days, and your price per kWh. The calculation applies the same draw, usage, and rate throughout the selected period.
How it works
- Enter the appliance's power draw at the wall in watts (W); use an actual or representative draw rather than assuming its rated maximum is constant.
- Enter hours of use per day (0-24), the number of days, select a currency, and enter your local electricity price per kWh in that currency.
- Read the estimated energy in kWh and cost in your selected currency.
Example use cases
- Desk lamp: A 10 W lamp used 5 hours a day for 30 days uses 1.5 kWh. At 0.20 currency units per kWh, the estimated energy charge is 0.30 currency units.
- Portable heater: A 1,500 W heater running 2 hours a day for 10 days uses 30 kWh. Multiply 30 kWh by the applicable price per kWh to estimate its variable energy cost.
Frequently asked questions
Should I enter the appliance's rated wattage?
Enter its representative power draw while operating. A nameplate maximum may differ from typical use, and devices that cycle or change power can use less or more over time than a constant-wattage estimate.
Does the estimate match my full electricity bill?
No. It estimates energy cost from the entered per-kWh price. Fixed service charges, taxes, changing rates, and other household loads are not included.