Battery Life Calculator
Estimate how long your battery will last given capacity, load current, and efficiency.
Estimated runtime (real)
1.4 days
34.0 h at 85% efficiency
Ideal runtime (100% eff)
1.7 days
Frequently Asked Questions
Why is the real runtime lower than ideal?+
Batteries can't deliver 100% of their rated capacity due to internal resistance, temperature, and the cut-off voltage of the circuit. Typical efficiency for Li-ion is 80–90%.
How do I reduce current draw?+
Use sleep modes on microcontrollers, turn off peripherals when idle, switch to lower-power radios (LoRa vs. Wi-Fi), and use a low-quiescent-current LDO regulator.