Use our interactive calculator to easily convert amp hours to kilowatt hours (Ah to kWh):
Amp Hours to Kilowatt Hours Conversion Calculator
Or would you rather convert kilowatt hours to amp hours?
Amp Hours to Kilowatt Hours Conversion Chart
Here is a conversion chart converting common amp hour values to kilowatt hours at 12 and 24 volts.
| Amp Hours | Kilowatt Hours (12V) | Kilowatt Hours (24V) |
|---|---|---|
| 100 Ah | 1.2 kWh | 2.4 kWh |
| 200 Ah | 2.4 kWh | 4.8 kWh |
| 300 Ah | 3.6 kWh | 7.2 kWh |
| 400 Ah | 4.8 kWh | 9.6 kWh |
| 500 Ah | 6 kWh | 12 kWh |
| 600 Ah | 7.2 kWh | 14.4 kWh |
| 700 Ah | 8.4 kWh | 16.8 kWh |
| 800 Ah | 9.6 kWh | 19.2 kWh |
| 900 Ah | 10.8 kWh | 21.6 kWh |
| 1000 Ah | 12 kWh | 24 kWh |
How to Convert Amp Hours to Kilowatt Hours (Ah to kWh)
To convert amp hours to kilowatt hours, multiply amp hours times volts, then divide by 1000.
Formula: kilowatt hours = amp hours × volts ÷ 1000
Abbreviated: kWh = Ah × V ÷ 1000
Example: How to Calculate Kilowatt Hours of a Battery
For example, let's say you own this lithium battery:
To calculate battery capacity in kilowatt hours, first locate its amp hours (Ah) and voltage (V). As you can see, these are printed right on the front of the battery. It has a capacity of 100 amp hours and a voltage of 12 volts.
Knowing these, we can now calculate its kilowatt hours. Here's how to do it:
100 Ah × 12 V ÷ 1000 = 1.2 kWh
So, in this example, your battery has a capacity of 1.2 kilowatt hours.
Why Convert Amp Hours to Kilowatt Hours?
Its common for battery sizes to be listed in amp hours. This is helpful when comparing batteries with the same voltage. It's easy to deduce that a 12V 50Ah battery has half the capacity of a 12V 100Ah battery, for instance.
But, once you start to compare batteries of different voltages, only comparing their amp hours can lead to confusion. This is because the total energy a battery can provide depends on both its amp hours and voltage.
For example, let's say you have a 12V 100Ah battery and a 24V 100Ah battery. If you look at their amp hours, you see they're identical. Both are 100Ah batteries. You may assume, then, that they hold the same amount of energy.
You'd be wrong. Like I said, the amount of energy stored in a battery depends on its amp hours and voltage. To take both of these into account, you need to calculate a battery's kilowatt hours.
So you calculate the kilowatt hours of both of your batteries.
You learn the 12V 100Ah battery has a capacity of 1.2 kWh:
100 Ah × 12 V ÷ 1000 = 1.2 kWh
And the 24V 100Ah battery has a capacity of 2.4 kWh:
100 Ah × 24 V ÷ 1000 = 2.4 kWh
That's right -- the 24V 100Ah battery stores twice as much energy as the 12V 100Ah battery.
The bottom line is, if you're comparing batteries of different voltages, you need to compare their kilowatt hours rather than their amp hours.
Converting amp hours to kilowatt hours is also helpful when sizing batteries. Energy usage is usually listed in watt hours or kilowatt hours, so calculating a battery's kilowatt hours helps you figure out how long the battery can power the device or appliance.
For instance, if you have some LED lights that consume 100 watt hours a day, a 1 kilowatt hour battery can power them for about 10 days before needing to be recharged.
Note: This is a very simplified scenario. In reality, battery capacity depends on a host of factors including things like discharge rate, battery age, battery chemistry, and ambient temperature.
Watt Hours vs Kilowatt Hours (Wh vs kWh)
1 kilowatt hour is equal to 1000 watt hours, like how 1 kilometer is equal to 1000 meters. So, to convert kilowatt hours to watt hours, you simply multiply kilowatt hours times 1000.
Formula: watt hours = kilowatt hours × 1000
Abbreviated: Wh = kWh × 1000
Going back to the example above of the 1.2 kWh lithium battery, if you wanted to instead express the battery's capacity in watt hours, you'd do the following:
1.2 kWh × 1000 = 1200 Wh
So, your lithium battery has a capacity of 1.2 kilowatt hours, or 1200 watt hours.
Note: You'll usually see battery capacities of less than 1 kilowatt hour expressed in watt hours. For instance, it's more common to see a battery marketed as having a capacity of 300 watt hours rather than 0.3 kilowatt hours.
How to Convert Kilowatt Hours to Amp Hours (kWh to Ah)
To convert kilowatt hours to amp hours, multiply kilowatt hours times 1000, then divide by volts.
Formula: amp hours = kilowatt hours × 1000 ÷ volts
Abbreviated: Ah = kWh × 1000 ÷ V
Example
Let’s say you have a 5 kWh solar generator. You look through the product manual and learn that its battery has a voltage of 48 volts. Here’s how to calculate its amp hours using that info:
5 kWh × 1000 ÷ 48 V = 104.17 Ah
So the battery in your solar generator has a capacity of 104.17 amp hours.
How to Convert Amp Hours to Watt Hours (Ah to Wh)
For smaller batteries, it’s common to see their capacity expressed in watt hours (Wh) rather than kilowatt hours (kWh).
To convert amp hours to watt hours, you just multiply amp hours times volts.
Formula: watt hours = amp hours × volts
Abbreviated: Wh = Ah × V
Calculator: Amp Hours to Watt Hours Calculator
Example
Let's say you own this lead acid battery:
From the battery label you can see that it's a 12 volt, 33 amp hour battery. Here's how to calculate its watt hours:
33 Ah × 12 V = 396 Wh
So the battery has a capacity of 396 watt hours.
You could express its capacity in kilowatt hours by dividing 396 by 1000 (396 ÷ 1000 = 0.396). So you could also say it's a 0.396 kilowatt hour battery.
Easy!
How to Convert Milliamp Hours to Kilowatt Hours (mAh to kWh)
For even smaller batteries -- such as those in phones, tablets, and other handheld devices -- you'll often see their capacities given in milliamp hours (mAh).
When comparing battery life across similar devices, it can be helpful to convert milliamp hours to watt hours, or even kilowatt hours.
To convert milliamp hours to kilowatt hours, multiply milliamp hours times volts then divide by 1,000,000. (Yep, 1 million.)
Formula: kilowatt hours = milliamp hours × volts ÷ 1,000,000
Abbreviated: kWh = mAh × V ÷ 1,000,000
Example
Let's say your phone's battery has a capacity of 3500 milliamp hours and a voltage of 3.7 volts. Here's how to calculate its capacity in kilowatt hours:
3500 mAh × 3.7 V ÷ 1,000,000 = 0.01295 kWh
Your phone battery has a capacity of 0.01295 kilowatt hours, or 12.95 watt hours.
Note: Like I said, it's more common to see battery life for batteries of this size given in watt hours rather than kilowatt hours.
