Lithium Battery Watt Hour Calculator: (mAh / Ah ↔ Wh)

Last Updated: March 3, 2023

Use our lithium (LiFePO4) battery watt-hour calculator to convert the battery capacity from amp hours (Ah), or milliamp hours (mAh) to watt hours (Wh).

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Lithium (LiFePO4) battery watt-hour calculator

Note: 1000 milliamp hours is equal to 1 amp.

How to use this calculator?

1 - Enter the battery capacity and select the unit type. The unit types are amp-hours (Ah), and milliamp-hours (mAh). For example, if you have a 100ah battery, enter 100 and select the unit type to Ah.

2 - Enter the battery voltage. Is this a 6v, 12v, 24v, or a 48v battery? It should be mentioned on the specs sheet of your battery or on the battery itself.

3 - Optional: Enter the number of batteries if you're using multiple batteries. (Default value will be 1)

example: how many watt-hours are in a lithium battery?

**Screenshot from the calculator:** How many watt hours in a 100ah lithium battery?

100Ah lithium battery is equal to 1200 watt-hours of usable energy.

How do you calculate lithium battery watt-hours?

Multiply the battery capacity in amp-hours (Ah) by the battery voltage to calculate watt hours (Wh).

Formula: Battery capacity Watt-hours = Battery capacity Ah × Battery voltage

Example

Let's say you have a 12v 200ah lithium battery.

12v 200Ah battery into watt hours = 200 × 12 = 2400Wh

Lithium Battery amp-hours to Watt Hour Calculation

Here's a chart about different capacity (Ah) lithium batteries into watt hours @ 12v, 24, and 48v.

Battery Ah	watt-hours @ 12v	watt-hours @ 24v	watt-hours @ 48v
20Ah	240 Wh	480 Wh	960 Wh
50Ah	600 Wh	1200 Wh	2400 Wh
70Ah	840 Wh	1680 Wh	3360 Wh
100Ah	1200 Wh	2400 Wh	4800 Wh
120Ah	1440 Wh	2880 Wh	5760 Wh
150Ah	1800 Wh	3600 Wh	7200 Wh
200Ah	2400 Wh	4800 Wh	9600 Wh
300Ah	3600 Wh	7200 Wh	14,400 Wh
400Ah	4800 Wh	9600 Wh	19,200 Wh

Why calculate battery watt-hours?

Energy is equal to amp-hours multiplied by volts. Converting battery amp hours to watt-hours will give an idea of how much actual energy your battery can store or deliver.

For example, A 36v 12.8ah battery can store or deliver more energy than a 12v 30ah battery.

36v * 12.8ah = 460.8Wh

12v * 30ah = 360Wh

The benefit of converting battery amp hours to watt-hours:

Makes it easy to calculate the battery runtime on a specific load. The energy or power consumption for most of the appliances is mentioned in watts or watt-hours. So, converting battery capacity in watt hours will make it easy for you to estimate the battery runtime on a load.

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Chris Tsitouris

Chris Tsitouris is a renewable energy professional with 10+ years of experience as Director of Engineering at Solar Spectrum, previously working as Project Manager at SunPower and Energy Analyst at the National Renewable Energy Laboratory. As a thought leader, Chris has authored numerous articles and research papers.