wh to mah calculator

Wh to mAh Calculator

Convert a battery's watt-hour rating into milliamp-hours when you need to compare power banks, labels, or airline capacity limits.

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Watt-hours (Wh)Voltage (V)

Voltage presets

Use the voltage printed on the battery label when available. mAh without voltage cannot be compared fairly.

Converted capacity

27,027 mAh

mAh = Wh x 1000 / volts

Watt-hours100 Wh

Amp-hours27.03 Ah

Milliamp-hours27,027 mAh

Voltage3.7 V

Travel check: At or below 100 Wh, lithium-ion spare batteries are within the standard FAA PackSafe size limit, but airline, route, and damage-protection rules still apply. Check the FAA PackSafe lithium battery page and your airline before flying with spare batteries or power banks. Reviewed 2026-06.

Estimate runtime Find power station size

Converted capacity27,027 mAh

ModeWh to mAh

Watt-hours100 Wh

Voltage3.7 V

Result27,027 mAh

WattRunTime battery capacity conversion

WattRunTime battery capacity conversion
Mode: Wh to mAh
Input: 100 Wh
Voltage: 3.7 V
Result: 27,027 mAh
Watt-hours: 100 Wh
Travel note: At or below 100 Wh, lithium-ion spare batteries are within the standard FAA PackSafe size limit, but airline, route, and damage-protection rules still apply.
Use the voltage printed on the battery label when available. mAh without voltage cannot be compared fairly.

At or below 100 Wh, lithium-ion spare batteries are within the standard FAA PackSafe size limit, but airline, route, and damage-protection rules still apply.

Use Wh to mAh when a power-bank label expects mAh

This direction starts with energy already known in Wh and converts it into a voltage-specific mAh label for comparison.

Formula focus

mAh = Wh x 1000 / V. A 100 Wh pack is about 27,027 mAh at 3.7 V, but only 20,000 mAh at 5 V.

Best use case

Use this when comparing power-bank listings or checking whether a Wh-rated pack lines up with a mAh claim.

Power Station Capacity Runtime Guides