๐ Battery Life Calculator
Leave efficiency at 100% for a rough estimate if you don't know it.
Runtime20h 0m20 hours
Estimate how long a battery will last, given its capacity, the device's current draw, and the power conversion efficiency. Useful for estimating runtime for power banks or battery-powered devices.
How to use
- Enter the battery capacity (mAh).
- Enter the device's current draw (mA).
- Enter the power conversion efficiency (%) โ leave at 100% if unknown.
- The runtime is calculated automatically.
FAQ
What is conversion efficiency?
It represents power lost when the battery's output is converted for the device, e.g. via a DC-DC converter โ typically below 100%.
What formula is used?
Runtime (h) = battery capacity (mAh) ร (efficiency% รท 100) รท current draw (mA).
Why might the real runtime differ from this estimate?
Actual runtime varies with the battery's discharge curve, temperature, and load changes, so treat this as an estimate only.