How the ZC Power Portable Generator Calculator Works

Our calculator follows the same methodology our 80 technical engineers use when sizing units for client projects around the world.

First, we total the running watts of every piece of equipment you intend to power simultaneously. Next, we identify the highest starting watts demanded by any single motor-driven load—typically compressors, submersible pumps, or arc welders. The minimum generator output equals the sum of total running watts plus that single highest starting surge.

From there, we apply a 20 to 25 percent safety margin to account for voltage fluctuations, future load additions, and temperature derating. Finally, we convert your total kilowatt requirement into kVA using a standard industrial power factor of 0.8, which is how commercial generator sets are rated globally.

If your site sits above sea level, the calculator also applies altitude derating—roughly 3 percent power loss for every 1,000 feet of elevation. This is a step most consumer calculators skip, yet it is critical for highland mining and infrastructure projects.