# Milliamp Hours to Watt Hours (mAh to Wh) Conversion Calculator

Updated:

Watt-Hours Results:

mAh × V / 1000 =

0.00 Wh

Conversion formula: Wh = mAh × V / 1000

## What Is Milliamp-Hours (mAh)?

Milliamp-hours is short for milliampere-hours. It is a unit that measures how much electric charge a power source will discharge over a one hour period at a specific voltage.

Milliamp-hours, sometimes written as mAh, is usually used as a measure of battery capacity. It gives a general idea of how long a battery will last/give off electric charge before it needs a recharge. For instance, a battery rated 5000 mAh would be expected to last longer than a 3800 mAh when used to power the same device.

## What Is Watt-Hours (Wh)?

Watt-hours is a unit of energy (more times than not, electrical energy). It is a measure of how much energy is absorbed or discharged by an electrical device when the device produces or uses a certain amount of power over time.

In essence, one watt-hours is the amount of electrical energy produced when one watt of is power generated or used over one hour.

Like milliamp-hours, watt-hours may be used as a measure of battery capacity. However, in many cases, battery makers opt for milliamp-hours or amp-hours.

## Why Convert Milliamp-Hours to Watt-Hours?

Converting milliamp-hours (mAh) to watt-hours (Wh) is useful when comparing the capacity of batteries, especially when the batteries have different voltages.

If we compare the mAh of batteries with different voltages directly, we’d only be comparing the amount of electric charge they give off over one hour. But such comparison may be limiting. If we want an encompassing comparison, we have to compare the batteries’ energy storage capacity.

For clarity, say we have two batteries A & B and A is rated 2000 mAh 5 volts while B is 2000 mAh 8 volts. Both batteries will discharge the same amount of electric charge (2000 mA) over one hour. However, battery B will store more energy than A since its Wh would be 16 Wh while that of A is 10 Wh.

## How to Convert Milliamp-Hours to Watt-Hours (mAh to Wh)

### mAh to Wh Conversion Formula

To derive the mAh to Wh conversion formula, we need the formula for electrical energy (Wh).

Electrical energy is a product of power and time. Going by that, we can represent it as:

electrical energy (Wh) = power (W) x time (h) (1)

Now, that we have the formula for electrical energy, we need the formula for power. With the formula for power, we’ll expand W into quantities that can show the relationship between Wh and mAh.

Power equals voltage multiplied by current (amperage). So, we can represent it as:

power (W) = voltage (v) x current (A) (2)

Now, we’ll substitute power for voltage x current into (1):

electrical energy (Wh) = voltage (v) x current (A) x time (h) (3)

(3) can be rewritten as:

Wh = v x Ah (4)

In (4), we have the formula for converting amp-hours (Ah) to watt-hours (Wh). But to get the formula to convert mAh to Wh, we need the formula to convert milliamp-hours to amp-hours.

Amp-hours equals the milliamp-hours divided by 1000:

Ah = mAh/1000 (5)

So, if we substitute Ah for mAh/1000 into (4), we’ll get the formula for an mAh to Wh conversion:

Wh = v x mAh/1000

Basically, to convert milliamp-hours (mAh) to watt-hours (Wh), we’ll multiply milliamp-hours times voltage then divide by 1000. Then to do the reverse – convert watt-hours to milliamp-hours – we’ll multiply watt-hours by 1000 then divide by voltage.

So, to convert Wh from mAh, enter voltage and mAh in their corresponding fields on our mAh to Wh calculator & mAh becomes Wh.

### Conversion Examples

What’s the battery capacity of a 5000 mAh, 3 v average C battery in watt-hour?

To get this battery’s capacity in watt-hours, all we have to do is multiply 5000 milliamp-hours times 3 v then divide by 1000:

3 x 5000/1000

= 15 Wh

A 12 v battery has an amperage of 360 mA and an average battery life of 7 hours when it powers a solar flood light. What is the energy in watt-hours the flood light consumes?

To solve this, we’ll calculate the battery capacity in milliamp-hours (mAh) by multiplying the battery’s amperage by battery’s life:

360 x 7 = 2520 mAh

Next, we’ll calculate energy e in watt-hours (Wh) by multiplying milliamp-hours times voltage and dividing by 1000:

2520 x 12/1000 = 30.24 Wh

How much energy in watt-hours is stored in a power bank rated 30,000 mAh and 24 volts?

We can solve this by simply multiplying milliamp hours times volts before dividing by 1000:

30,000 x 24/1000 = 720 Wh

## Milliamp Hours to Watt Hours Conversion Chart

As mentioned earlier, to convert to Wh from mAh, enter voltage in the given spaces on our mAh to Wh calculator & mAh becomes Wh. But what if a conversion calculator is not readily available?

When a milliamp-hours to watt-hours conversion calculator is not available, quick conversion charts like those below can come in handy:

For a 12v battery:

 mAh Wh 1000 12 2000 24 3000 36 4000 48 5000 60 6000 72 7000 84 8000 96 9000 108 10,000 120

For a 20v battery:

 mAh Wh 1000 20 2000 40 3000 60 4000 80 5000 100 6000 120 7000 140 8000 160 9000 180 10,000 200

For a 24v battery:

 mAh Wh 1000 24 2000 48 3000 72 4000 96 5000 120 6000 144 7000 168 8000 192 9000 216 10,000 240

## The Difference Between Amp-Hours (Ah) and Milliamp-Hours (mAh)

Amp-hours and milliamp-hours are both units that represent battery capacity. They are typically used as a measure of how much electric charge a battery can store. Better still, they define how much electric charge a battery can discharge over one hour at a specific voltage.

While very similar, Ah and mAh differ in magnitude. While amp-hours (Ah) measures in units, milliamp-hours (mAh) measures in thousandths (1/1000). Basically, the values Ah represents are generally larger than those mAh represents.