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Battery Life Estimator

Physics & Engineering

Estimate battery life in hours based on battery capacity and device current draw.

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mAh
1 mAh1,000,000 mAh
mA
0.001 mA100,000 mA

Estimated Battery Life

13.3

Estimated battery life in hours at this current draw, assuming a constant discharge rate.

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Odeh Ahwal

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Odeh Ahwal
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Frequently Asked Questions

Does this calculator account for varying current draw over time?

No, this assumes a constant current draw — real devices often have variable power consumption, such as a phone using more power with the screen on, so actual battery life can differ from this simplified estimate.

What is mAh?

Milliamp-hours, abbreviated mAh, measure battery capacity, the total charge a battery can deliver — a higher mAh rating generally means longer battery life for the same current draw, all else being equal.

Why might real-world battery life be shorter than this estimate?

Battery efficiency decreases at high discharge rates, batteries lose some capacity over their lifespan, and not all of the rated capacity is usable before voltage drops too low for the device to function, all of which can make real-world life shorter than a simple calculation suggests.

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