Generator sizing calculator
Select what has to keep running. We add continuous draw, put the largest motor start on top, and leave 20% headroom — then name the unit that covers it.
What has to stay on
Your result
—kW
Recommended capacity
0 W
Continuous running load
0 W
Peak with largest motor start
0
Loads selected
Sizing adds 20% headroom over peak demand. Motor loads are counted at their starting surge, one at a time, which is how a generator actually experiences them. Final sizing is confirmed against your panel and nameplate data before install.