Why Windows Battery Life Estimates Often Differ From Real-World Runtime

A Windows battery report may show around five hours of runtime while a coding session lasts only about two, and this gap alone does not indicate a faulty battery. The key distinction is between stored energy, which reflects battery capacity, and power demand, which depends on the workload. The article explains how to generate a battery report with powercfg and read the Battery life estimates section, which separates projections at full charge from comparisons using design capacity. Using simplified examples, it shows that doubling power draw roughly halves idealized runtime even when capacity stays the same. It recommends logging controlled unplugged sessions under consistent conditions, since the estimates are based on recorded history that may not reflect heavy tasks.