Battery Runtime Calculator
How long a pack lasts at a steady load: capacity ÷ current. Not watt-hours.
Runtime is capacity ÷ load. Real packs sag, devices cut out before empty, and the draw is not constant. No voltage is used, so this is not watt-hours.
Runtime
12h 0m 0s
12 hours at a steady load
Worked example
A 3,000 mAh battery with a steady 250 mA load runs for 12h 0m 0s — that's 3,000 ÷ 250, which is 12 hours.
FAQ
- Does this include the device switching itself off?
- No. It's capacity divided by a constant load. Real packs sag, and devices cut out before empty.
- Can I use watt hours?
- Only if you convert first. This page doesn't take voltage, so it is not watt-hours.
- What units are these?
- Capacity is milliamp hours. Load is milliamps. The result is hours, minutes, and seconds.