Lights On HQ

Power Station Runtime Calculator: What Size Do You Need?

Estimate how many watt-hours and peak watts you need to run your devices through an outage, then see which models match.

Disclosure: Lights On HQ is reader-supported. If you buy through links on this page we may earn a commission, at no extra cost to you. Research-based data, not hands-on tested. Full disclosure · Methodology.

Safety first: Never connect a power station to your home wiring by plugging it into a wall outlet (“backfeeding”). It can kill utility workers and start fires. For whole-circuit backup, use a transfer switch or inlet installed by a licensed electrician. CPAP users: check power needs and humidifier use with your equipment provider or doctor before relying on battery power. Don’t run space heaters on a power station; they drain even large units in about an hour.

Add the devices you want to run during an outage. Wattages are typical estimates; check the label on your device for real numbers.

Watts Hours/day Qty

DeviceWattsStartup WHoursQtyWh

Math: Wh needed = sum of (watts × hours × qty) ÷ 0.85 inverter efficiency. Peak = running watts of everything on at once, plus the largest single startup surge. Model specs from our spec database, prices checked Oct 16, 2026. Results are estimates, not guarantees.

☀️ Charging with solar? Try the Solar Charge Time Calculator, or see how long you’d last in the Blackout Survival Challenge.

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