What size generator do I need?
Tick everything you want running at the same time. We add the running watts, then add only the single biggest start-up surge, because motors rarely start in the same instant. Wattages are typical values for each type of appliance, not measurements; check your own labels.
How this is worked out
- Running watts: sum of every ticked appliance at full running draw (no duty-cycle discount, which rounds the size up).
- Starting watts: running total plus the largest single (start-up minus running) among the ticked items.
- Headroom: 30% added to both, so the generator is not run flat out. Classes: running output must cover the first figure and starting capability the second.
- Class sizes are common market ratings (peak assumed about 125% of running for portables). Your exact model's spec sheet decides; compare both numbers.