This calculator estimates how long a battery will last, based on its nominal capacity and the current or power that a load is drawing from it.

The results are estimates only; the actual results will vary with battery condition, age, temperature, discharge rate, and other factors. The predicted results will best represent actual results when using new, high-quality cells at room temperature when the estimated run time is between 1 hour and 1 year.

Battery Life

Battery Capacity
Device Consumption
Battery Life Formula

Battery Life = Battery Capacity in mAh / Load Current in mAh


*This is an estimated output, based on ideal conditions.