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Amp Hour Calculator

Amp Hour Calculator

The calculator will calculate amp hours needed to drive a certain load.

Select :

I want to calculate:



Battery Capacity






Load Size

Load Duration

Temperature Adjustment :
Age Adjustment :


Table of Content

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This free amp hour calculator that is specifically designed to calculate amp hours from watts that corresponds to the battery amp hour calculations. 

How Does Our Amp Hour Calculator Work?

Here’s how you can use this battery ampere calculator :


Simple Mode:

  • From the first drop-down list, select the parameter you wish to calculate
  • After this, enter the required ones in their respective fields
  • Now tap the calculate button

Advanced Mode:

  • Enter the load size and load current in designated fields
  • You can also set the battery age and heat adjustments along with its type
  • After you are done with the stuff, it’s time to hit the calculate button


The amp hour battery calculator provides the following reactions to your actions:

  • Calculate battery capacity, runtime to full capacity, and discharge current ratio
  • Also, the battery load calculator displays the amps of battery that would be enough to run your desired load

What is a Battery Amp Hour?

In the dictionary of electrical engineering science:

“One Amp Hour is the amount of charge flowing through battery in one single hour”

Our battery amp hour calculator 12v is specially designed for this purpose.

Formula to Calculate Battery Capacity

Battery Ah calculations are quite easy if you understand the following physical equations:

P = V*I


E = V * I * T (As Power multiplied by Time equals Energy)


E = V*Q (As current rate over time is equal to the charge flowing through battery)

The same equation is utilized by our battery amp hours calculator to calculate battery Ah.The ampere and the flow of current can be variable in an area.

How to Calculate Amp Hours Without Using a Battery Stuff Calculator ?

Let’s find out the capacity of battery as we have the number of voltages and energy stored in it without utilizing an amps to amp hours calculator:

  • We are going to take a typical battery having 12 volts.
  • Get the amount of energy stored in the battery e.g 27.
  • Use the following formula

E = V * Q

Q = 27 / 12

Q = 2.25 Ah

Practical Example


Suppose you have just bought a battery of 20 V and the charge stored in it is approximately 20Wh. Then how to calculate battery amp hours in this case?


By using the formula, we can better do battery power calculations in terms of its amp hour as follows:

E = V*Q

E = 20*20

E = 400

The free battery Ah calculator also does the same computations but saving you a lot of time.

Amp Hour Running Chart:

The following chart has been arranged after recording the amp hours of various electrical devices operating for different time durations (1h, 2h, 4h, 8h). Let’s go through these!

Device Wattage

Ah Needed For 1h Run Time Ah Needed For 2h Run Time Ah Needed For 4h Run Time Ah Needed For 8h Run Time
10 Watt 0.83 Ah (830 mAh) 1.67 Ah 3.33 Ah

6.67 Ah

20 Watt

1.67 Ah 3.33 Ah 6.67 Ah 13.33 Ah
50 Watt 4.17 Ah 8.33 Ah 16.67 Ah

33.33 Ah

100 Watt

8.33 Ah 16.67 Ah 33.33 Ah 66.67 Ah
150 Watt 12.50 Ah 25.00 Ah 50.00 Ah

100.00 Ah

200 Watt

16.67 Ah 33.33 Ah 66.67 Ah 133.33 Ah
250 Watt 20.83 Ah 41.67 Ah 83.33 Ah

166.67 Ah

300 Watt

25.00 Ah 50.00 Ah 100.00 Ah 200.00 Ah
350 Watt 29.17 Ah 58.33 Ah 116.67 Ah

233.33 Ah

400 Watt

33.33 Ah 66.67 Ah 133.33 Ah 266.67 Ah
450 Watt 37.50 Ah 75.00 Ah 150.00 Ah

300.00 Ah

500 Watt

41.67 Ah 83.33 Ah 166.67 Ah 333.33 Ah
600 Watt 50.00 Ah 100.00 Ah 200.00 Ah

400.00 Ah

700 Watt

58.33 Ah 116.67 Ah 233.33 Ah 466.67 Ah
800 Watt 66.67 Ah 133.33 Ah 266.67 Ah

533.33 Ah

900 Watt

75.00 Ah 150.00 Ah 300.00 Ah 600.00 Ah
1,000 Watt 83.33 Ah 166.67 Ah 333.33 Ah

666.67 Ah

1,500 Watt

125.00 Ah 250.00 Ah 500.00 Ah 1,000.00 Ah
2,000 Watt 166.67 Ah 333.33 Ah 666.67 Ah

1,333.33 Ah

2,500 Watt

208.33 Ah 416.67 Ah 833.33 Ah 1,666.67 Ah
3,000 Watt 250.00 Ah 500.00 Ah 1,000.00 Ah

2,000.00 Ah

4,000 Watt

333.32 Ah 666.68 Ah 1,333.33 Ah 2,666.68 Ah
5,000 Watt 416.65 Ah 833.35 Ah 1,666.67 Ah

3,333.35 Ah

10,000 Watt

833.33 Ah 1,666.67 Ah 3,333.33 Ah

6,666.67 Ah

You can also let this battery amp hour calculator provide swift aid in cross verification of all the values in the table above. How does it sound to you?


How many Ah is a 12V car battery?

Such a battery has an amp range of about 50Ah that you could also verify by using this battery amp calculator.

How long can a 100Ah battery run a TV?

A 100Ah battery would be able to run a 32-inch LED TV for 30 minutes and 50-inch LED TV for up to 15 minutes.

How Many Solar Panels Does it Take to Charge a 100Ah Battery?

A 610 Wattage solar system would be sufficient to charge a 100Ah battery that is lithium based ionised. But remember that the rating is true only when there are peak sun hours running.

How Many Amps can a 12v Battery Supply?

A local 12v battery would produce 600 Amperes per hour that could be also verified by this ah battery calculator.


From the source of Wikipedia: Ampere hour, Use, Other measures of electric charge,

From the source of Khan Academy: Defining the standard electrical units, Electric current, Current direction

From the source of Lumen Learning: Current, Drift Velocity

From the source of Libretexts: Electric Current Current and Voltage Measurements in Circuits, Drift Speed