Emergency Generator Sizing Calculator

Calculate emergency generator size based on fire pump, elevator, lighting, and life safety loads.

Fire pump motor horsepower. Common: 15-200 HP. Enter 0 if no fire pump.
HP
Elevator motor horsepower for fire service recall. Enter 0 if not required.
HP
Total emergency and exit lighting load in kilowatts.
kW
Fire alarm, smoke control, and communication systems total load.
kW
Smoke control fans, stairwell pressurization, IT/server rooms, etc.
kW

Results

Total Connected Load-kW
Demand Load (0.8 factor)-kW
Generator Size-kVA
Fuel Consumption (diesel)-gal/hr
Runtime at 500 gal Tank-hours
References: NFPA 110 — Emergency and Standby Power Systems, NEC Article 700-702.