Enter your power station's watt-hour capacity and the load you'll run to see how many hours it lasts.
Most lithium power stations reserve 5-10% capacity and lose 5-15% more to inverter conversion — usable runtime is always somewhat less than the rated Wh divided by load.
A power station's watt-hour rating is its total stored energy, but not all of it reaches your device — DC-to-AC inversion loses some as heat. This is the same math used by our full home battery backup runtime calculator, scaled down to portable units for camping, CPAP machines, or laptop charging in the field.
Manufacturers list watt-hour capacity prominently on the box, but that number alone doesn't tell you what you actually need to know: how long it will keep your specific devices running. Multiplying capacity by efficiency and dividing by your load closes that gap, and it's worth doing before a trip or an outage rather than during one.
Inverter conversion losses and a battery management system's protective reserve both cut into usable capacity — 85-95% of rated Wh reaching the load is typical.
Add their wattages together to get total load — the same formula applies whether it's one device or several running simultaneously.
Add up the wattage of everything running simultaneously and enter that combined total as your load — the calculator doesn't need to know the device count, just the total draw.