Technology
Battery Life Calculator
Find battery life from capacity and drain.
Formula
Life = capacity ÷ drain.
How it works
For example, 4000 mAh ÷ 400 mA = 10 hours.
FAQs
What does the Battery Life Calculator do?
It takes the values you enter and works out the battery life calculator for you, showing the result straight away.
What should I enter?
Enter ordinary numbers in the boxes above. If a value does not make sense for this calculation, the page will ask you to check it instead of showing a wrong answer.
Can I use the result for everyday math?
Yes. It is a general-purpose math helper; for professional work, still check the steps against your own working.
Instant result, no sign-up.
All tools are free.
Each page shows the formula it uses, so you can check the result yourself.
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