Battery Life Calculator

Your details

Choose whether to calculate runtime or the capacity needed to achieve a target runtime.
Continuous: the device draws current at one steady rate. Sleep-cycle: the device alternates between an active phase and a low-power sleep phase.
The rated capacity printed on the battery.
mAh and Ah are the most common units on datasheets and battery labels. Use Wh when you know the energy but not the voltage.
Average current the device draws during normal operation.
Real-world batteries deliver less than their rated capacity due to temperature, age, and the cut-off voltage. 80% is a typical conservative estimate; 100% assumes ideal conditions.
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Estimated runtimeDay-scale runtime
16hours

How long the battery will last under the given load

Runtime in days0.67days
Runtime in weeks0.1weeks
Average current draw150mA
Capacity used in calculation2,400mAh
16 h
Under 1 hour<1Hours1-8Days8-72Extended72+

Estimated runtime: 16.00 hours (0.67 days).

  • Runtime is 16.0 hours, which is less than one full day.
  • For day-long use you may want to increase capacity or reduce the load.
  • This uses 2400 mAh of usable capacity after the efficiency derating.
  • Real-world runtime will vary with temperature, battery age, and whether peak currents exceed the steady average used here.

Next stepSwitch to "Sleep-cycle" mode if your device uses a microcontroller or radio with sleep states.

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