Battery capacity is measured in milliampere-hours (mAh), which indicates how much electric charge a battery can store. In simple terms, a higher mAh rating means the battery can supply power for a longer period before needing a recharge.
For example, a 5,000mAh battery can theoretically deliver 5,000 milliamps for one hour, or 1,000 milliamps for five hours. However, real-world battery life also depends on factors like processor efficiency, display brightness, network usage, and software optimization. So while mAh gives an idea of capacity, it does not guarantee exact screen-on time.