About the kWh Calculator
Convert watts and hours into kilowatt-hours, or work back from kWh to power or time.
Also known as: kilowatt hour calculator, watts to kwh, kwh from watts, energy consumption kwh.
How to use this calculator
- Enter solve for.
- 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 ÷ 1000 × hours
Worked example
Using the values pre-filled in the calculator above:
- Solve for: Kilowatt-hours
- Power = 1,500 W
- Hours = 4
the calculator returns:
- Energy: 6 kWh
- In watt-hours: 6,000
- In megajoules: 21.6
- In BTU: 20,472.9