Battery Life Calculator

Estimate battery runtime based on capacity, load current, and discharge efficiency

Basic Calculator
V
%
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Battery Types
Typical Characteristics
  • Li-ion 3.7V
  • LiPo 3.7V
  • NiMH 1.2V
  • Lead-Acid 2V/cell
  • Alkaline 1.5V
Select battery type above to auto-fill typical voltage and efficiency values.
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Help Guide

Battery capacity is typically measured in mAh (milliampere-hours) or Ah (ampere-hours). This represents how much current the battery can supply over time.

Real-world batteries don't deliver 100% of their rated capacity. Li-ion batteries typically achieve 80-90% efficiency, while lead-acid may be only 70-80% efficient.

The C-rate is the rate at which a battery is discharged relative to its maximum capacity. A 1C rate means the discharge current will discharge the entire battery in 1 hour.