If you've ever wondered how long a battery really lasts or whether a power bank can fully charge your device, you're not alone. In the world of batteries and portable power sources, we often encounter two units: mAh (milliampere-hours) and Wh (watt-hours). While mAh can be found on almost every battery label, Wh plays a crucial role when it comes to actual energy capacity, safety regulations (e.g., in aviation), and comparing different batteries.
In this guide, we'll show you how to convert mAh to Wh, why this conversion is so important for applications such as camping solar batteries, e-bike batteries, power stations, or mobile devices – and how you can use it to make better purchasing decisions or plan your system more efficiently.
Contents
- What do mAh and Wh actually mean?
- Why is converting mAh to Wh important?
- The conversion formula – mAh to Wh
- mAh to Wh calculator
- Examples of conversion
- Bonus: Conversion also in the other direction – Wh to mAh
- Conclusion
What do mAh and Wh actually mean?
The terms mAh (milliampere-hours) and Wh (watt hours) We often encounter these terms when choosing rechargeable batteries or batteries – but what exactly do they mean?
- mAh (milliampere-hours) indicates how much power a battery can supply over one hour. It is a unit of measurement for capacity – the higher the number, the longer the battery will last during operation.
👉 Example:
A battery with 5,000 mAh can theoretically supply 5,000 mA (i.e., 5 A) for 1 hour.
- Wh (watt-hours), on the other hand, indicates how much energy is stored in total – that is, the actual power output over time. This value is particularly important when it comes to better estimating the energy consumption of a device or comparing different battery types.
Why is converting mAh to Wh important?
Converting mAh (milliampere-hours) to Wh (watt-hours) is important for several reasons – especially when comparing energy content or planning electricity consumption and supply. Here are the main reasons why this conversion is so crucial in practice:
Realistically compare energy content
- The mAh rating alone does not reveal how much energy a battery can actually deliver.
- Only by converting to Wh, taking into account the voltage (volts), can the actual energy content be determined.
📌 Example:
A 3,000 mAh battery at 3.7 V delivers 11.1 Wh – a 3,000 mAh battery at 12 V, on the other hand, delivers 36 Wh.
➡️ Same mAh, but three times the energy content!
Accurately estimating device consumption
- Many electrical appliances (e.g., laptops, coffee machines, solar panels) specify their consumption in watts or watt-hours.
- To calculate how long a battery can power a device, you need Wh.
🛠️ Formula:
Runtime (hours) = Battery Wh ÷ Device wattage
Making purchasing decisions easier
- Manufacturers often only specify capacity in mAh – especially for power banks, rechargeable batteries and batteries from Asia.
- Anyone who knows how to convert mAh to Wh can objectively compare products and expose unrealistic advertising promises.
System planning for off-grid, motorhomes, solar storage
- In energy planning, every watt-hour counts. Only with watt-hours (Wh) can you configure battery systems tailored to your needs.
- How large does my solar storage system need to be?
- Is 1200 Wh enough for one night of self-sufficient camping?
- How long will my 800-watt inverter run?
The conversion formula – mAh to Wh
Converting mAh to Wh is very easy – you can use this formula directly. However, if you find the calculation too complicated, the table below provides an overview of common mAh values and their corresponding Wh conversions. This allows you to easily look up the data you need.
Wh = (mAh × V) ÷ 1000
| milliampere-hours (mAh) | Voltage (V) | Watt-hours (Wh) |
|---|---|---|
| 5000 mAh | 12.8 | 64 Wh |
| 10000 mAh | 12.8 | 128 Wh |
| 10400 mAh | 12.8 | 133.12 Wh |
| 12000 mAh | 12.8 | 153.6 Wh |
| 13000 mAh | 12.8 | 166.4 Wh |
| 15000 mAh | 12.8 | 192 Wh |
| 20000 mAh | 12.8 | 256 Wh |
mAh to Wh calculator
A mAh-to-Wh calculator can help you flexibly convert between mAh and Wh – we provide you with a simple calculator here:
mAh to Wh calculator
Examples of conversion
A mAh-to-Wh calculator helps you quickly convert your battery's capacity – but what do these numbers actually mean in everyday use? To give you a better understanding of real-world scenarios, we've compiled practical examples from various areas such as motorhomes, fishing, camping, and mobile power supply in the table below:
| Application | Battery (mAh) | Voltage (V) | Calculated energy (Wh) | Example of use |
|---|---|---|---|---|
| Motorhome | 100,000 mAh | 12.8 V | 1280 Wh | Power supply for refrigerator, pump, laptop, etc. |
| Trolling motor | 20,000 mAh | 24 V | 480 Wh | Electric propulsion on the water |
| Camping power station | 15,000 mAh | 12 V | 180 Wh | LED lights, smartphone charging |
| Mobile working | 10,400 mAh | 12.8 V | 133.12 Wh | Operate the notebook for approximately 2 hours |
| electric boat | 10.000 mAh | 36 V | 360 Wh | Boat navigation or small devices |
Bonus: Conversion also in the other direction – Wh to mAh
In the previous section, we explained how to convert mAh to Wh. However, converting Wh to mAh is just as useful in everyday life. You can either use the following formula or simply use our handy Wh-to-mAh calculator to quickly and easily calculate the values.
mAh = (Wh × 1000) ÷ V
Wh to mAh calculator
Conclusion
Converting mAh to Wh – and vice versa – plays an important role in many areas of everyday life, whether buying a battery for a camper van, using power banks for fishing, or understanding product specifications. With the formulas, examples, and practical calculators presented here, you'll be well-equipped to select the right battery for your needs and accurately assess its capacity. Use our tools to save time and make informed decisions.
