How do you calculate generator fuel consumption?

A common rule of thumb is that a generator burns about 0.015 gallons per hour per kW of load at half capacity. Our calculator provides a specific estimate based on generator electrical size and applied load.

What is the most fuel efficient generator?

Diesel generators are generally the most efficient per gallon, followed by gasoline inverter generators. Propane has less energy density than gas, often resulting in slightly shorter runtimes for the same tank volume.

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GeneratorCalc

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Generator Fuel Consumption & Runtime

Estimate how many gallons of fuel your generator burns per hour and how long a full tank will last at your expected load.

Calculate Your Fuel Usage

Enter your generator specs below to get an instant estimate.

Generator Rated Watts

Load Percentage (%)

Tank Size (gallons)

Fuel Type

How This Calculator Works

This tool uses standard fuel consumption rates for portable generators. Results are estimates based on:

Generator wattage: Larger generators use more fuel.
Load percentage: Running at 50% load uses less fuel than 100%.
Fuel type: Diesel is most efficient, propane least.

For exact specifications, always refer to your generator's manual.

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