About the Watt Hours Calculator
Convert battery amp-hours and voltage into watt-hours, and back again.
Also known as: ah to wh, wh to ah, battery watt hours, battery energy calculator.
How to use this calculator
- Enter calculate, nominal voltage.
- 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
Wh = Ah × V
Worked example
Using the values pre-filled in the calculator above:
- Calculate: Watt-hours
- Capacity = 100 Ah
- Nominal voltage = 12 V
the calculator returns:
- Energy: 1,200 Wh
- Watt-hours: 1,200
- Amp-hours: 100
- Kilowatt-hours: 1.2