mAh to Wh Calculator
Batteries are rated in milliamp-hours, but airlines and shipping rules often use watt-hours. This converts one to the other.
- Free
- Works offline after your first visit
- Saves on this device
- No sign-up
- Updated
How it works
Watt-hours equal the milliamp-hours divided by one thousand, times the battery's voltage. The voltage is set by the battery chemistry, not the charger.
Most lithium cells are around 3.6 to 3.85 volts. The number on the battery label is the best source for the exact voltage.
Worked example
A 5,000 mAh battery at 3.7 V holds 18.5 Wh.
Questions
Why do I need the voltage?
A milliamp-hour is a measure of charge, and watt-hours is a measure of energy. Voltage links the two.
Where do I find the voltage?
Check the label on the battery or the device's manual. If you cannot find it, the typical lithium figure of 3.7 volts is a fair starting point.
Why do rules use watt-hours?
Shipping and travel rules often set limits in watt-hours, so converting lets you compare a battery to those limits.
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