Start with watt-hours
Multiply watts by hours for each load. A router at 14W for eight hours is a very different job than a fridge cycling through the night.
Outage backup planner
Size a power station around the loads you actually care about.
Pick the essentials, adjust the assumptions, and get a rough watt-hour target before shopping for a budget power station.
Suggested class500Wh class
A small overnight setup for phones, router, and lights.
Sizing notes
How to use the outage backup estimate
The capacity estimate multiplies each device's energy-average watts by hours, then adds an 18% buffer for inverter and battery losses. Continuous output uses actual running watts. Running and start entries are per device, so quantity multiplies both. The system peak assumes all units of one selected load start together while every other selected load is already running.
Check running and surge watts
Continuous watt rating matters for steady loads. Surge rating matters for motors, compressors, pumps, and anything that spikes when it starts.
Match battery size to charging plan
A larger battery is only useful during a long outage if you have a realistic wall, car, generator, or solar recharge path.
Next checks
Read before you choose a model
Portable power station sizing
Translate watt-hours into a realistic shopping range.
Read guide300Wh vs 500Wh vs 1000Wh
See how the common size classes fit different backup jobs.
Read guidePower station runtime calculator
Check how long one device can run from a common battery size.
Open calculator