kWh To Ah Conversion (Calculator: Input kWh And V, Get Ah or mAh)

How do I convert kilowatt-hours to amp-hours?

In many cases, we need to convert kWh to Ah. With smaller 12V batteries, we also need to convert kWh to mAh.

We will look into how does kWh to amp-hours (Ah) conversion. You will also find a kWh to Ah calculator that dynamically calculated kWh from Ah and a calculated table of kWh to Ah and kWh to mAh. Let’s start with an example to illustrate.

Example: How to convert 13.5 kWh to Ah? First, we need to specify the voltage. Let’s say we have a 12V battery. We can calculate Ah from kWh using the basic kilowatt-hour equation:

kWh = Ah × V × 1,000

We express amp-hours (Ah) and insert our numbers:

Ah = kWh ÷ V × 1,000

Ah = 13.5kWh ÷ 12V × 1,000 = 1,125 Ah

That means that 13.5 kWh is equal to 1,125 Ah or 1,125,000 mAh on a 12V circuit.

Here is the kWh to Ah calculator that makes this calculation automatically:

kWh To Ah Calculator

Just insert kWh and voltage (V), and you will get the calculated Ah. You can also play around with numbers a bit and the calculator will dynamically calculate the ampere-hours:

 

For example, it is useful to know this basic conversion:

1 kWh to Ah in a 12V battery is equal to 83.33 Ah.

On the other hand, if you need an Ah to kWh conversion, you can find a similar Ah to kWh conversion calculator here.

Here is the full calculated table of kWh to Ah conversions for the 12V circuit:

kWh To Ah And kWh to mAh Chart (At 12V; For Batteries)

kWh (kilowatt-hours) Ah (amp-hours) mAh (milliamp-hours)
0.01 kWh 0.83 Ah 830 mAh
0.02 kWh 1.67 Ah 1,670 mAh
0.025 kWh 2.5 Ah 2,500 mAh
0.05 kWh 4.17 Ah 4,170 mAh
0.1 kWh 8.33 Ah 8,330 mAh
0.5 kWh 41.67 Ah 41,670 mAh
1 kWh 83.33 Ah 83,330 mAh
2 kWh 166.67 Ah 166,670 mAh
10 kWh 833.33 Ah 833,330 mAh
20 kWh 1,666.67 Ah N/A
50 kWh 4,166.67 Ah N/A
100 kWh 8,333.33 Ah N/A

If you have any questions about how to convert these two electrical units, you can pose a question in the comments and we’ll help you out.

14 thoughts on “kWh To Ah Conversion (Calculator: Input kWh And V, Get Ah or mAh)”

  1. I am trying to determine how many Ah 12V battery I will need to power my 115VAC refrigerator for 48 hours.
    I used a watt meter and found that my frig uses 1.04 kWh in 48 hours.

    If I use an inverter that is 90% efficient I am coming up with approximately 91Ah of 12V battery. Does that seem correct?

    Reply
    • Hello Brent, if your fridge uses 1.04 Wh in 48 hours, you basically need a battery that can produce 1.04 kWh of output. That would be 1040 Wh/12V = 86.7Ah battery (at 100% battery efficiency). Of course, you also have to account for 90% efficiency.

      That 1.04 kWh should represent 90% of the battery capacity. Here is how you account for that: 86.7 Ah / 0.9 = 96.3Ah. So, you would need at least a 96.3Ah 12V battery. That’s practically your standard 100Ah battery. Hope this helps.

      Reply
  2. Hi,
    I power 2 led lights of 72watts @ 220v. If a run these on battery setup of 24V with inverter how much will a 100Ah battery last…?

    Reply
    • Hello there, so 2 LED lights with 72W each required a total of 144W power. A 12V 100Ah has a capacity of 1,200Wh and will run both of them for 1,200Wh/72W = 16.7 hours. If you have a 24V 100Ah battery, it will have double the capacity (2,400Wh) and will run the lights for double the time (33.3 hours). Hope this helps.

      Reply
  3. Hello I have a solar system 8 panels; inverter and 4 battery (200A each) for night
    Can I keep the fridge (730kwh/year) all night in power without damaging the battery
    Thanks for your help

    Reply
  4. Hi
    Please I want to know the difference between lithium battery rated in kWh and tubular batteries rated in ah and their application in designing a solar inverter system

    Reply
    • Hi there, that’s completely understandable. The battery capacity should always be expressed in watt-hours (Wh) or kWh. That’s the ‘real’ capacity. In most cases, however, battery capacity is expressed in amp-hours (like your tubular batteries).

      You have to put both batteries on the same denominator, and the kWh is the best unit for that. Here’s how you can do that: Let’s say you have 1000 Ah tubular batteries that run on a 12V DC current. To get the Wh, you simply multiply the Ah by voltage and you get 12,000 Wh capacity. This is a 12 kWh capacity. If you have lets say 10 kWh lithium battery, you can now compare these two battery capacities apple-to-apple. Hope this makes sense.

      Reply
  5. I have an extra second generation Toyota Prius battery, It is a 201.6-volt NiMH (nickel metal hydride battery) battery composed of 28 modules where EACH of the 28 modules is comprised of SIX individual 1.2-volt, 6.5 Ah (6500mAh) Prismatic NiMH cells which are internally connected in series. Each 7.2-volt module contains a charge controller and a relay. It’s basically a giant 201.6 Volt DC battery!
    I was going to replace the bad cells & use it as a battery back up for my home.
    Is is better to step down to 120v from 201.6 or re-configure it to 24 or 48 volts then to 120v ? or if you have any suggestions

    Reply
    • Hi Simon, that’s quite an interesting question. The 201.6-volt battery is just awesome. We have to admit that we don’t have enough knowledge to adequately advise here. However, it seems like decreasing 201.6V to 120V directly just makes sense. Decreasing to 24V or 48V and then back up to 120V is maybe overthinking this. Hope you get it done, all in all it’s a brilliant idea.

      Reply
  6. This was super useful. Thanks for the info. The Q&A examples really helped me to understand.
    On the last question they mentioned the 201V battery as lots of small batteries in series. Have you done anything on how that works? Series v parrel?

    Reply
    • Hi Craig, thank you. Well, we are talking about in-series vs parallel wiring here; the voltage and amperage are different for each wiring. However, we are always looking at the net output (and input). When you have kWh, V, Ah, these are all net values and the difference between in-series vs parallel doesn’t reply apply here. Hope this helps.

      Reply
  7. Hi
    Our electricity usage is 45kwh in summer to 70 kwh in winter per day.
    it was recommended that we install the following
    16kw Inverter
    3 * 5Kwh batteries
    12 * 540 watts solar panels
    2 * 63amps circuit breakers
    I have no idea it this is correct

    Reply
    • Hi there, well, first you have to think about the kWh usage. 12×540W = 6480W solar panels. In the US, for example, we have 5-7 peak sun hours, which means such a system will produce 32.4 kWh to 45.4 kWh per day. This could fulfill all your electricity needs in the summer (45 kWh/day) but not in the winter.

      With the 3×5 kWh batteries, you will have 15 kWh of storage. That is in line with what you should have (maybe a bit low). The 63 amp circuit can be loaded up to 80% max. capacity; so they facilitate 50.4 amp draw. At 12V (battery voltage), this is 604.8 watts. Two of them would facilitate 1209.6-watt power. This seems low for a 6480W system. Probably, you will have to talk to some installers.

      Reply

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