Generator Fuel Consumption Calculator

Estimate generator fuel consumption and run time from tank capacity.

About Generator Fuel Consumption Calculator

Specific fuel consumption is best near 75 per cent load and worsens sharply below 30 per cent. Fuel cost per kWh from a diesel generator is typically several times the grid price. Fuel is the dominant cost of generator operation, so runtime on a tank and cost per kWh are the two figures that drive both logistics and budget.

Formula

Generator Fuel Consumption

Consumption = output kW × specific fuel consumption in litres per kWh

specific fuel consumption: Litres per kWh generated, worst at light load

Worked example

With the default values below, Generator Fuel Consumption Calculator returns Fuel Consumption of 7.560. Change any input above and every figure here is recalculated in your browser.

Inputs used

Generator outputminimum 0 kW: 40 kW
Loadingaccepts 0–100 %: 70 %
Specific fuel consumptionminimum 0.05 L/kWh: 0.27 L/kWh
Fuel tank capacityminimum 0 L: 200 L
Fuel price per litreminimum 0: 1.5

Results

Fuel Consumption: 7.560 L/h
Runtime on a Full Tank: 26.46 h
Fuel Cost per Hour: $11.34
Fuel Cost per kWh Generated: $0.4050
Consumption Running 24 Hours: 181.44 L

Step by step

1Values used
2Generator Fuel Consumption
3Fuel Consumption= 7.560 L/h
4Runtime on a Full Tank= 26.46 h
5Fuel Cost per Hour= 11.34
6Fuel Cost per kWh Generated= 0.4050
7Consumption Running 24 Hours= 181.44 L

Assumptions and limits

The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Generator Fuel Consumption calculated?

Consumption = output kW × specific fuel consumption in litres per kWh Specific fuel consumption is best near 75 per cent load and worsens sharply below 30 per cent. Fuel cost per kWh from a diesel generator is typically several times the grid price.

Why does Generator Fuel Consumption matter?

Fuel is the dominant cost of generator operation, so runtime on a tank and cost per kWh are the two figures that drive both logistics and budget.

What values do I need to enter?

This calculator takes 5 inputs: Generator output, Loading, Specific fuel consumption, Fuel tank capacity, Fuel price per litre. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.