Generator Fuel Consumption Calculator

Roughly linear, but not perfectly. Generators are most fuel-efficient at 70-80% load. At very low loads (below 30%), efficiency drops significantly and diesel engines can suffer from wet stacking, where unburned fuel accumulates in the exhaust system.

Load is the total wattage of all devices powered by the generator as a percentage of its rated capacity. A 10 kW generator running a 5 kW total load is at 50% load.

A portable 5 kW generator typically consumes 1.5 to 2.5 litres per hour at 50-75% load. A larger 20 kW standby generator uses 4 to 8 litres per hour depending on load and fuel type.

Diesel generators are typically 15-25% more fuel-efficient than petrol generators of the same size. Diesel also has a longer shelf life and diesel engines generally last longer, though they cost more upfront.

Run the generator at 50-80% of rated capacity for optimal efficiency. Turn off unnecessary loads, use energy-efficient appliances, and maintain the generator regularly. Avoid running generators below 30% load for extended periods.

Multiply the hourly consumption rate by hours per day, then by days per month, then by fuel price per litre. For example: 5 L/hr x 8 hours x 30 days x $1.80/L = $2,160 per month.

Yes, embedding the Generator Fuel Consumption Calculator is free. Hit the "Embed" button on this page, adjust the width, height, and theme, then grab the iframe code. It works on WordPress, Wix, Squarespace, Shopify, and plain HTML pages. No registration needed. Full instructions at calculory.com/services/embed-calculators.