Ah to Wh Converter Calculator

Convert battery capacity into energy with voltage and efficiency. Compare scenarios and view practical outputs. Plan loads accurately using clear formulas, tables, and downloads.

Battery Conversion Form

Use the responsive input grid to convert amp-hours into watt-hours and estimate usable battery energy.

Example Data Table

Capacity Voltage Quantity DoD Efficiency Total Wh Usable Wh
12 Ah 12 V 1 100% 100% 144 Wh 144 Wh
100 Ah 12 V 1 80% 95% 1,200 Wh 912 Wh
50 Ah 24 V 2 90% 92% 2,400 Wh 1,987.2 Wh
2,600 mAh 3.7 V 1 90% 85% 9.62 Wh 7.36 Wh

Formula Used

Basic conversion: Wh = Ah × V

From milliamp-hours: Wh = (mAh ÷ 1000) × V

Total nominal energy: Total Wh = Ah × V × Quantity

Usable energy: Usable Wh = Total Wh × (DoD ÷ 100) × (Efficiency ÷ 100)

Runtime estimate: Runtime (hours) = Usable Wh ÷ Load Watts

Amp-hours measure charge capacity, while watt-hours measure actual energy. Voltage links both measurements, so higher voltage produces more watt-hours from the same amp-hour rating.

If you connect identical batteries in series, voltage rises and amp-hours stay constant. In parallel, voltage stays constant and amp-hours increase. Total energy remains proportional to battery count in either case.

How to Use This Calculator

  1. Enter the battery capacity and select Ah or mAh.
  2. Provide the nominal voltage for one battery.
  3. Set the number of identical batteries and choose the connection type.
  4. Add depth of discharge and system efficiency for a realistic usable energy estimate.
  5. Enter average load in watts to estimate runtime.
  6. Choose the number of decimal places you want.
  7. Press Convert Now to display results above the form.
  8. Use the CSV or PDF buttons to download your calculated output.

Frequently Asked Questions

1. What is the basic Ah to Wh formula?

Multiply amp-hours by volts. A 100 Ah battery at 12 V stores 1,200 Wh before depth-of-discharge, efficiency, temperature, and aging limits are applied.

2. Why do I need voltage for this conversion?

Amp-hours alone measure charge, not energy. Voltage is required because watt-hours represent electrical work, and energy equals charge multiplied by voltage.

3. Does series or parallel wiring change total watt-hours?

With identical batteries, total watt-hours mainly scale with battery count. Series raises voltage, parallel raises amp-hours, but overall stored energy stays comparable.

4. What does usable watt-hours mean?

Usable watt-hours reflect real energy after applying depth-of-discharge and efficiency losses. This gives a more practical estimate for runtime and system planning.

5. Can I convert mAh to Wh here?

Yes. Select mAh as the input unit. The calculator first converts milliamp-hours to amp-hours, then multiplies by voltage to produce watt-hours.

6. Why is the runtime estimate only approximate?

Actual runtime changes with inverter losses, battery age, temperature, discharge rate, wiring losses, and load spikes. The estimate is best for planning, not guarantees.

7. Can I use this for solar, RV, UPS, or marine batteries?

Yes. The method works for any battery system when you know capacity, voltage, battery count, expected usable discharge, and approximate efficiency.

8. What do the download buttons export?

The CSV export saves labeled results in spreadsheet-friendly format. The PDF export creates a concise report of the current calculation results.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.