Wh to mAh Calculator

Convert watt-hours to milliamp-hours at any voltage. Reverse of mAh to Wh, useful for power banks and airline battery limits.

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Formula

Milliamp-hours = watt-hours × 1000 ÷ volts (mAh = Wh × 1000 ÷ V). Higher voltage means fewer mAh for the same energy

Examples

InputResult
74 Wh at 3.7 V20,000 mAh
100 Wh at 3.7 V27,027 mAh
100 Wh at 5 V20,000 mAh

Frequently Asked Questions

How do you convert Wh to mAh?

Divide watt-hours by voltage and multiply by 1000: mAh = Wh × 1000 ÷ V. 74 Wh at 3.7 V is 20,000 mAh; the same 74 Wh at 12 V is only 6,167 mAh.

Why do power bank mAh ratings look huge?

They are measured at the 3.7 V cell voltage, while USB output is 5 V. A '20,000 mAh' bank stores 74 Wh, at 5 V that is only about 14,800 mAh of output before conversion losses.

Is mAh a measure of energy?

No, mAh is charge. Energy (Wh) = charge (Ah) × voltage. Comparing mAh across different voltages is meaningless; convert to Wh first.

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