Ah to Wh Calculator
Convert amp-hours to watt-hours.
Interactive Electrical Calculator
Ah to Wh Calculator
Convert amp-hours to watt-hours.
Result
Enter values and calculate.
About the Ah to Wh Calculator
The Ah to Wh Calculator handles battery capacity, runtime, charging time and series/parallel bank sizing without needing a spreadsheet, app download or manual lookup table. Convert amp-hours to watt-hours. Series and parallel wiring change voltage and capacity in very different ways, and getting it backwards can damage cells or leave a system under-powered.
It's built for solar and off-grid system builders, RV and marine owners, backup-power installers, and hobbyists working with lithium or lead-acid packs, and every field updates instantly so you can try a few scenarios before committing to a real installation.
How the calculation works
The calculator is built around this relationship:
Wh = Ah × V.
Where each input maps to a field in the calculator above:
- Capacity in Ah.
- Voltage in V.
Change any field above and the result recalculates immediately — nothing is submitted anywhere, so it's safe to experiment freely.
A worked example
For example, start with 100 Ah for capacity and 12 V for voltage. That's a reasonable starting point to explore from: nudge one value up or down and watch how much the result shifts before you commit to a final design figure.
When to use the Ah to Wh Calculator
Typical reasons people reach for the Ah to Wh Calculator:
- Sizing a battery bank for a specific backup runtime target.
- Working out how long a charger will take to top up a given battery.
- Converting a battery spec sheet between Ah, Wh and mAh so it can be compared with another product.
- Planning a series/parallel wiring configuration to hit a target system voltage and capacity.
Good practice: Wiring batteries in series adds their voltages while capacity (Ah) stays the same as a single cell; wiring in parallel adds capacity while voltage stays the same.
Also worth knowing: Real-world runtime is usually shorter than a simple capacity ÷ load calculation because of inverter losses, temperature and battery age.
Frequently asked questions
What does the Ah to Wh Calculator calculate?
Convert amp-hours to watt-hours.
Can I rely on this number for a real installation?
The formula above is applied exactly to the values you enter, so the math itself is precise. Real-world results can still differ due to component tolerances, temperature, installation method, equipment efficiency and local code requirements, so treat the output as a strong planning estimate and verify final designs against manufacturer data and the electrical code that applies to your installation.
Does this calculator store or send my data anywhere?
No. The Ah to Wh Calculator runs entirely in your browser, and nothing you type is transmitted or stored anywhere.
Why does this calculation matter in practice?
Charging time depends on charger current, battery capacity and charge efficiency together, not on any one of those numbers alone.
Will this work for both metric and everyday values?
The Ah to Wh Calculator works on any modern browser, phone or desktop, and recalculates as soon as you press Calculate. If a result looks off, double-check that every field is filled in with the unit shown next to it (mixing up units, such as W with kW, is the most common cause of an unexpected answer) and re-enter the values.