Generator calculator
Fuel Cost and Runtime Calculator
Estimate outage fuel cost and storage-limited runtime from your generator load, fuel type, fuel use, fuel price, and available fuel.
Screening estimate only.These calculators use only the values you enter. A licensed electrician's load calculation is authoritative before equipment is selected or installed.
Screening result
Fine Print and Sources
Screening estimate only. These tools use only the values you enter and simple planning math. A licensed electrician's load calculation is authoritative for equipment selection, transfer equipment, permitting, fuel piping, and final installation scope.
Fuel cost and runtime vary by exact model, load, maintenance condition, fuel pressure, altitude, and the fuel units used by your local supplier. The fuel derate note is based on Generac's 20 kW example, which lists 20,000 W on liquid propane and 17,000 W on natural gas.
- Generac 20 kW product specifications: lists 20,000 W maximum continuous power on liquid propane and 17,000 W on natural gas for the cited example.