Amp Hour to Watt Hour Calculator
Convert battery capacity from amp-hours to watt-hours using voltage, with optional usable-capacity and efficiency adjustments. Enter your own values and review the assumptions shown with the result.
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The main result is shown first, followed by supporting values that make the calculation easier to verify.
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How to Use This Calculator
Enter each requested value using the displayed unit. Review the assumptions and update the defaults when your situation differs.
Formula & Methodology
The calculator applies the visible formulas directly to the entered values. Supporting outputs expose important intermediate results.
Worked example
A 100 Ah, 12 V battery stores 1,200 Wh nominally. At 80% usable capacity and 90% efficiency, estimated delivered energy is 864 Wh.
Battery voltage changes with state of charge and load. Rated amp-hours depend on discharge rate, temperature, chemistry, age and manufacturer test conditions.
Planning estimate only. Follow manufacturer limits and use qualified electrical guidance for wiring, protection and high-energy battery systems.
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Frequently Asked Questions
- What does the Amp Hour to Watt Hour Calculator calculate?
- Convert battery capacity from amp-hours to watt-hours using voltage, with optional usable-capacity and efficiency adjustments.
- Can I change the assumptions?
- Yes. Replace the example values with inputs that match your situation and review every unit before using the result.
- Is the result exact?
- No. The result is an estimate produced by the displayed formula and the values entered. Real-world outcomes may differ.
- Should important results be verified?
- Yes. Verify important decisions with official documentation, measured data, product instructions or a qualified professional.
Last updated 7/22/2026