How watt sizing works
Running vs surge, class ladder, and CO / backfeed safety.
Inverter generator sizing
Generator watts size calculator
Enter continuous (running) and starting (surge) watts. Get the smallest 1800 / 3200 / 6800 W inverter class — or NO_MATCH. Outdoor use only; never backfeed house wiring.
Inverter generator sizing
Result
Match the smallest class where running ≥ your continuous watts AND peak ≥ your surge watts. Classes: 1800/2900 · 3200/4200 · 6800/10000. Above the ladder → NO_MATCH. Outdoor only; CO risk; never backfeed house wiring.
From measurement to decision
Open the full calculator
Same tool with room for examples.
1800 vs 3200 vs 6800 classes
When each class fits — and when none do.
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