Battery Runtime Calculator
How long a battery lasts at a given load.
Runtime
12h 0m 0s
Worked example
A 3,000 mAh battery with a steady 250 mA load runs for 12h 0m 0s, because 3,000 ÷ 250 is 12 hours.
FAQ
- Does this include the device switching itself off?
- No. It is capacity divided by a constant load. Real devices change their draw, and a battery is not used down to a true zero.
- What units are these?
- Capacity is milliamp hours. Load is milliamps. The result is hours, minutes, and seconds.
- Can I use watt hours?
- Only if you convert first. This page does not take voltage.