Calculator
Estimate how long a propane or diesel generator may run on a given fuel supply — and understand the different situation for utility natural gas.
Fuel Type
Common sizes: 100-gal cylinder, 250-gal, 500-gal, 1,000-gal tank.
20 kW at 50% load
LP tanks are filled to a maximum of 80% capacity per NFPA 58, reserving 20% as vapor headspace for safe thermal expansion. Runtime is based on the 80% usable volume, not the tank's nominal rating.
Estimate only. Fuel consumption varies with load profile, ambient temperature, altitude, engine age, and maintenance condition. These figures are based on typical residential standby generator spec sheets and are intended for planning purposes only. Consult your generator's specification sheet for precise data.
