Glossary · Hardware

mAh (Milliampere-Hour)

mAh is a unit of battery charge capacity; a higher number generally means a battery can run a device longer, if voltage is comparable.

Updated October 6, 2026

mAh (milliampere-hour) is the unit used to express how much electric charge a battery holds. A 5000 mAh battery can theoretically supply 5000 milliamps for one hour, or 500 mA for ten hours.

Why it matters

mAh helps compare batteries in phones, power banks and wearables, but only at similar voltages. Energy in watt-hours (Wh), which is voltage times capacity, is a more complete measure.

Real runtime depends on screen use, radios, temperature and software efficiency.

Example

5000 mAh at 3.85 V = 5 Ah x 3.85 V = 19.25 Wh

Power bank 10000 mAh at 3.7 V = 37 Wh
Output at 5 V loses some to conversion: roughly 6500 to 7500 mAh usable

Common mistakes

  • Comparing power banks and phones by mAh without considering voltage and conversion loss.
  • Assuming a bigger battery always means longer life regardless of the chip efficiency.
  • Charging to 100 percent and leaving it hot constantly, which ages the cell.

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