Conversions

mAh to Wh Calculator

Battery capacity is often given in mAh, but airlines and power stations use Wh. Convert between them with the battery’s voltage.

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mAh
V

Most lithium cells are 3.7 V; power banks often rate cells at 3.7 V.

Results

Energy
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Last updated June 30, 2026. Results update automatically as you type.

How it works

Watt-hours = mAh × volts ÷ 1000. For example, a 20,000 mAh cell at 3.7 V holds 74 Wh. Airlines usually limit carry-on power banks to 100 Wh without approval.

Frequently asked questions

Why convert mAh to Wh?

Airlines rate power bank limits in Wh, and it is the fair way to compare batteries at different voltages, since mAh alone ignores voltage.

What voltage should I use?

Use the cell voltage, usually 3.7 V for lithium. Some power banks print the Wh or the cell voltage on the label.

Is a higher mAh always more energy?

Not necessarily — energy (Wh) depends on both mAh and voltage. A higher-voltage pack can hold more energy at the same mAh.

These calculators provide general estimates for educational purposes only and are not financial advice. Real-world results depend on factors not captured here. Verify figures independently before making any purchase or financial decision.

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