TOOLS
Battery capacity calculator
Convert mAh to Wh, count phone charges, and add up the Wh your devices need during a power cut.
1. Convert mAh to Wh
If Wh is printed on the device or box, use that number. Otherwise calculate it from mAh and voltage.
- Watt-hour rating
- 37 Wh160 Wh or less. Up to two may be carried in the cabin, and none in checked baggage (some airlines are stricter).
2. How many phone charges
Check your phone's battery capacity (mAh and voltage) in the maker's specifications.
- Charges
- 1.9 chargesThis is a simple calculation. Conversion losses mean you will get fewer in practice.
3. Devices to run during a power cut
Power consumption (W) is on the device's rating label or in the manual.
Enter power and hours to calculate.
AC conversion loses some energy, so allow more capacity than calculated. If the manual gives run times, use those.
The results are estimates. If a product label, manual, or your local government gives different figures, follow those. What you enter is calculated on this page only and is not sent anywhere.
Read with
The guide explains where the numbers come from and how to choose, store, and rotate.
Choosing the capacity of power banks and portable power stations