About the Electrical Energy Calculator
Energy used by an appliance in kWh over a period, and what it costs to run.
Also known as: kwh calculator, appliance energy use, power consumption calculator, energy usage.
How to use this calculator
- Enter power rating, hours used per day, days, cost per kwh.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
kWh = watts × hours ÷ 1000
Worked example
Using the values pre-filled in the calculator above:
- Power rating = 1,500 W
- Hours used per day = 3
- Days = 30
- Cost per kWh = 0.28
the calculator returns:
- Energy used: 135 kWh
- Per day: 4.5 kWh
- Cost for the period: 37.8
- Cost per year: 459.9