Convert mAh to Wh and Wh to mAh - Conversion Calculator

Conversion between different units, especially when different unit prefixes are used is an ideal situation for making - mistakes.

If You need to convert mAh to Wh and Wh to mAh, feel free to use our unit conversion calculator.

Little Bit of Math and Physics

In order to convert mAh (milli Ampere-hours - battery capacity) to Wh (Watt-hours - energy, for example, stored in the batteries), we need to use this formula:

E (Wh) = U (V) * C (Ah)

where U (V) is a voltage of a battery or some other electric source.

If the battery capacity (C) is given in mAh, we must use these formulas:

C (mAh) = C (Ah) * 1000 → C (Ah) = C (mAh) / 1000

Thus:

E (Wh) = U (V) * C (Ah) = U (V) * C (mAh) / 1000

E (mWh) = U (V) * C (mAh)

For more about unit prefixes, feel free to check our SI Unit Prefixes: How Many Watts in Kilowatt? article.

For example:

LR44 battery is an 11.6 x 5.4 mm alkaline battery with an average voltage of 1.3 volts and an average capacity of ~120 mAh - this battery is thus able to store:

E (Wh) = U (V) * C (mAh) / 1000 = 1.3 V * 120 mAh / 1000 = 0.156 Wh = 156 mWh

SR44 battery is an 11.6 x 5.4 mm silver-oxide battery with an average voltage of 1.4 volts and an average capacity of ~200 mAh - this battery is thus able to store:

E (Wh) = U (V) * C (mAh) / 1000 = 1.4 V * 200 mAh / 1000 = 0.28 Wh = 280 mWh

As one can see, thanks to the larger average voltage and capacity, the silver-oxide SR44 battery is able to provide almost double the energy of the alkaline LR44 battery.

PR44 (Blue Tab) battery is an 11.6 x 5.4 mm zinc-air battery with an average voltage of 1.3 volts and an average capacity of ~650 mAh - this battery is thus able to store:

E (Wh) = U (V) * C (mAh) / 1000 = 1.3 V * 650 mAh / 1000 = 0.845 Wh = 845 mWh

Although zinc-air batteries have somewhat smaller voltage than silver-oxide batteries, thanks to their much larger capacity, they can store ~3x more energy than silver-oxide batteries and ~5x more energy than alkaline batteries.

But, zinc-air batteries use wet/moist electrolyte exposed to air and they dry out after several weeks, regardless if they are used or not. Thus, their use is limited - they are used as excellent hearing aid batteries.

mAh to Wh and Wh to mAh Conversion Calculators

In order to convert mAh to Wh and Wh to mAh, feel free to use these conversion calculators - write the values that You have and click 'Calculate' to convert them:

 MilliAmp-Hours (mAh) to Watt-Hours (Wh) MilliAmp-Hours (mAh): Volts (U): Watt-Hours (Wh): MilliWatt-Hours (mWh): Watt-Hours (Wh) to MilliAmp-Hours (mAh) Watt-Hours (Wh): Volts: MilliAmp-Hours (mAh): Amp-Hours (mAh):

Long Story Short: If You want to convert Amp-hours or milli-Amp-hours to Watt-hours or milli-Amp-hours, use our conversion calculator and/or these formulas:

E (Wh) = U (V) * C (Ah) = U (V) * C (mAh) / 1000

E (mWh) = U (V) * C (mAh)

And be careful about unit prefixes, of course.