Battery Life Calculator
Estimate battery runtime from battery capacity and device current draw.
How to Use the Battery Life Calculator
Enter battery capacity and device current draw to estimate approximate runtime.
Practical Example
A 5,000 mAh battery powering a 500 mA load has a simple theoretical runtime of about 10 hours.
Factors That Affect the Result
Battery chemistry, voltage conversion losses, age, temperature, discharge rate and device power spikes can reduce real runtime.
Frequently Asked Questions
Is the result exact?
No. It is an estimate.
Does battery age matter?
Yes.
Can efficiency losses be included?
Only if the calculator provides an efficiency input or you adjust assumptions manually.
Why Actual Battery Runtime Differs
Simple runtime estimates divide usable battery capacity by average load. Real batteries lose usable capacity because of discharge rate, temperature, age, conversion losses, voltage limits and device power variation. Treat the result as an estimate rather than a guaranteed operating time.