How Many mAh Is 100Wh?

The mAh equivalent of 100Wh depends on the battery voltage. At 3.7V, 100Wh is approximately 27,027mAh: (100 × 1,000) ÷ 3.7 ≈ 27,027mAh. At 5V, the same 100Wh equals 20,000mAh. This is why there is no single mAh value for 100Wh without knowing the voltage.

Can You Convert Wh to mAh Without Voltage?

No. Voltage is required to convert Wh to mAh because Wh measures energy while mAh measures electric charge. The same Wh capacity can correspond to different mAh values depending on the battery voltage. If the voltage is not immediately available, check the battery label or manufacturer specifications for its nominal or rated voltage.

How Do You Convert Watts to mAh?

Watts cannot be converted directly to mAh. Watts measure power, while mAh measures electric charge, so you also need the voltage and operating time. First calculate energy use: Wh = Watts × Hours Then convert Wh to mAh: mAh = (Wh × 1,000) ÷ V For example, a 100W device running for 2 hours uses 200Wh. At 12V, that corresponds to approximately 16,667mAh.

How Do You Convert 5,000mAh to Watt-Hours?

A 5,000mAh battery at 3.7V equals 18.5Wh. To calculate it, multiply the battery capacity in mAh by its nominal voltage, then divide by 1,000: Wh = (mAh × V) ÷ 1,000 (5,000 × 3.7) ÷ 1,000 = 18.5Wh The exact Wh value depends on the battery voltage. For example, 5,000mAh at 5V would equal 25Wh.

How Do You Convert kWh to mAh?

First, convert kWh to Wh using 1kWh = 1,000Wh. Then convert Wh to mAh using the battery voltage: mAh = (kWh × 1,000,000) ÷ V For example, 1kWh at 12V is approximately 83,333mAh. At 24V, the same 1kWh is approximately 41,667mAh, so voltage must always be included in the conversion.

Is a 20,000mAh Power Bank Equal to 100Wh?

Not necessarily. A 20,000mAh battery equals 100Wh only when calculated at 5V. Many power banks, however, state their mAh capacity based on the nominal voltage of their internal lithium cells. At 3.7V: (20,000 × 3.7) ÷ 1,000 = 74Wh So, a 20,000mAh power bank rated at 3.7V has an energy capacity of 74Wh. When converting a power bank's advertised mAh rating, check the voltage associated with the battery capacity rather than automatically using the 5V USB output voltage.

Wh to mAh Calculator: Formula & Conversion Chart

The Wh to mAh calculator converts battery capacity between watt-hours (Wh) and milliamp-hours (mAh) by accounting for both capacity and voltage. While mAh indicates how much electric charge a battery can hold, Wh reflects its energy capacity by factoring in voltage. This makes Wh useful for comparing batteries across different voltages, while converting Wh to mAh helps relate that energy capacity to the mAh ratings commonly shown on batteries and portable devices. For either direction, the conversion follows the same relationship between capacity and voltage: Wh = (mAh × V) ÷ 1,000, or mAh = (Wh × 1,000) ÷ V.

Wh to mAh Calculator

Use the calculator below for a quick Wh to mAh conversion or the reverse calculation. Enter the capacity you already know, select the conversion direction, and provide the battery's nominal voltage. The calculator will return the equivalent capacity automatically.

For the most accurate result, use the voltage associated with the battery's capacity rating rather than a charging or output voltage shown elsewhere in the device specifications.

Conversion direction Battery capacity (Wh) Nominal battery voltage (V)

Enter a capacity to calculate.

Use the battery's nominal or rated voltage, not the USB output or charging voltage.

How to Convert Wh to mAh

If your battery capacity is listed in watt-hours but you want to know the equivalent value in mAh, you will also need its voltage. With the Wh and voltage values, you can quickly calculate the battery capacity in mAh using the formula below.

Wh to mAh Conversion Formula

To convert Wh to mAh, you need both the battery's energy capacity in Wh and its voltage. This is because watt-hours depend on voltage and battery capacity (Wh = V × Ah). For the same Wh value, a higher voltage results in a lower mAh value.

mAh = (Wh × 1,000) ÷ V

If you have a 100Wh battery at 3.7V, you get:

(100 × 1,000) ÷ 3.7 ≈ 27,027mAh

But if the voltage is 5V, the same 100Wh battery gives you:

(100 × 1,000) ÷ 5 = 20,000mAh

This is why you should always use the battery's nominal or rated voltage, usually found on the battery label or product specifications. If several voltages are listed, use the voltage associated with the battery capacity rather than a charging or output voltage.

Wh to mAh Conversion by Steps

Converting Wh to mAh only takes a few steps:

Find the battery capacity in Wh.
Check its nominal voltage (V) on the battery label or specifications.
Multiply the Wh value by 1,000.
Divide the result by the voltage to get mAh.

For example, for a 160Wh battery at 12V:

160 × 1,000 = 160,000

160,000 ÷ 12 ≈ 13,333mAh

So, 160Wh is approximately 13,333mAh at 12V.

Wh to mAh Conversion Chart

Use this chart to quickly check common Wh to mAh conversions at 3.7V. At the same voltage, a higher Wh capacity corresponds to a higher mAh value.

Watt-Hours (Wh)	Voltage (V)	Milliamp-Hours (mAh)
1 Wh	3.7 V	≈270 mAh
24 Wh	3.7 V	≈6,486 mAh
37 Wh	3.7 V	10,000 mAh
100 Wh	3.7 V	≈27,027 mAh
160 Wh	3.7 V	≈43,243 mAh
256 Wh	3.7 V	≈69,189 mAh
290 Wh	3.7 V	≈78,378 mAh
300 Wh	3.7 V	≈81,081 mAh

If your battery uses a different voltage, use mAh = (Wh × 1,000) ÷ V to calculate the corresponding mAh value.

How to Convert mAh to Wh

Converting mAh to Wh tells you how much energy a battery stores based on its charge capacity and voltage. Since the same mAh capacity can represent different amounts of energy at different voltages, you need the battery's voltage to make the conversion.

mAh to Wh Conversion Formula

You need the battery's voltage to convert mAh to Wh, since the same mAh capacity can represent different amounts of energy at different voltages. Multiply the battery capacity in mAh by its voltage, then divide by 1,000:

Wh = (mAh × V) ÷ 1,000

For example, if you have a 20,000mAh battery at 3.7V, the calculation is:

(20,000 × 3.7) ÷ 1,000 = 74Wh

If that 20,000mAh battery operates at 5V instead, its energy capacity becomes:

(20,000 × 5) ÷ 1,000 = 100Wh

This means a 20,000mAh battery does not have one fixed Wh value. Its energy capacity in watt-hours depends on the battery voltage.

mAh to Wh Conversion by Steps

To convert mAh to Wh, follow these steps:

Find the battery capacity in mAh.
Check the battery's nominal or rated voltage.
Multiply mAh by the voltage, then divide by 1,000.

For example, to convert 4,000mAh to Wh at 3.7V:

4,000 × 3.7 = 14,800

14,800 ÷ 1,000 = 14.8Wh

So, 4,000mAh equals 14.8Wh at 3.7V.

mAh to Wh Conversion Chart

For quick reference, the table below shows common mAh to Wh conversions at 3.7V, a typical nominal voltage for single-cell lithium-ion batteries. If your battery has a different rated voltage, use that voltage to calculate the correct Wh value.

mAh	Voltage (V)	Watt-Hours (Wh)
1,000mAh	3.7V	3.7Wh
4,000mAh	3.7V	14.8Wh
5,000mAh	3.7V	18.5Wh
5,200mAh	3.7V	19.24Wh
10,000mAh	3.7V	37Wh
20,000mAh	3.7V	74Wh
40,000mAh	3.7V	148Wh

Wh vs. mAh Definition and Applications

Battery capacity may be expressed in different units depending on the product and specification. mAh ratings are commonly seen on smartphones, earbuds, and power banks, while Wh ratings are common on laptop batteries and portable power stations. For larger battery systems, the same energy capacity may be expressed in kWh for easier reference. Battery University also explains the relationship between voltage, Ah, and Wh.

Application	Unit	Typical Devices	Example
Small Electronics	mAh	Smartphones, earbuds, power banks	A 20,000mAh power bank is a common example of capacity expressed in mAh.
Remote Work	Wh	Laptop, phone, tablet	BLUETTI Elite 100 mini portable power station — 1,004.8Wh, suitable for laptops and mobile devices.
RV & Road Trips	Wh / kWh	RV fridge, lights, water pump	BLUETTI Elite 300 power station — 3,014Wh (3.014kWh), showing how larger battery capacity may also be expressed in kWh.
Home Backup	kWh	Refrigerator, Wi-Fi, essential appliances	BLUETTI Apex 300 home battery backup — 2.76kWh, with expandable capacity for longer backup.

Conclusion

Understanding the relationship between Wh and mAh makes it easier to read battery specifications and compare capacity across different devices. The key is to consider voltage rather than comparing the numbers alone, especially when batteries operate at different voltages.

Whether you're checking a power bank, laptop battery, or portable power station, converting between these units can give you a clearer picture of how their capacities compare. For specific values, use the Wh to mAh calculator above with the battery's nominal or rated voltage to get the correct conversion.