How long does a 12000 mah battery last?

The duration a 12,000 mAh battery lasts depends on the device's power consumption, measured in milliwatts (mW) or watts (W). For example, if a device consumes 1 watt (1,000 mW), a 12,000 mAh battery at 3.7 volts could last approximately 12 hours (12,000 mAh / 1,000 mW = 12 hours). However, if the device consumes more power, the battery life will decrease accordingly. Always consider the specific usage and efficiency of the device when estimating battery life.