Battery Capacity Converter
mAh, Ah and Wh for a battery, with the voltage the energy pair needs.
What is Battery Capacity?
Batteries are sold by milliamp-hours, which is a charge, while what they can do is measured in watt-hours, which is energy. Converting between the two needs the pack voltage, and a page that produces watt-hours from milliamp-hours without asking for the voltage has invented a number: 20 000 mAh is 74 Wh at 3.7 V and 100 Wh at 5 V. This one asks.
How it works
mAh and Ah differ by a factor of a thousand and convert with nothing else required. Watt-hours are amp-hours times volts, so the voltage is a required input for that pair — where it is missing the energy fields are absent rather than wrong. Joules are the same energy in SI, at 3600 per watt-hour, which is what a datasheet quoting energy in joules is telling you.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.