Fuel Consumption Calculator

Simple fuel economy checks for everyday driving

A good fuel consumption calculator helps you understand what your car is really using on a trip, not just what the dashboard suggests. Whether you measure fuel economy in mpg, litres per 100 km or km per litre, having a quick way to compare formats makes day-to-day driving costs much easier to track.

Built for UK drivers and international use

This tool is designed for people using miles and litres, kilometres and litres, or either UK or US gallons. That means you can switch between common systems without second-guessing the maths. If you know the distance travelled and fuel used, the result is calculated straight away. If you only know what you spent, you can enter the fuel price and total cost to estimate usage first.

Clear results without the clutter

A practical fuel economy calculator should be fast, readable and easy to use on mobile. This one keeps the layout focused on the essentials, then shows the main result along with helpful comparisons in other units. It also provides an estimated trip fuel cost when fuel price is available. For anyone comparing journeys, checking running costs or tracking efficiency over time, a reliable fuel consumption calculator saves time and removes the guesswork.

FAQs

What’s the difference between UK mpg and US mpg?

They’re based on different gallon sizes, which catches a lot of people out. A UK gallon is larger than a US gallon, so the same car will show a higher mpg figure in UK terms than in US terms. That’s why this calculator separates miles per gallon (UK) and miles per gallon (US), so you get a fair comparison instead of a misleading number.

Can I use this calculator if I only know how much I spent on fuel?

Yes, as long as you also know the fuel price per litre. The tool can work backwards by dividing the total fuel cost by the price per litre to estimate how much fuel was used, then it calculates fuel economy from there. It’s useful for drivers who top up at the pump and keep receipts rather than noting litres directly.

Which fuel economy format is best to use?

It depends on where you drive and what you’re comparing. In the UK, many drivers still think in mpg, especially for petrol and diesel cars. Across much of Europe and many other regions, litres per 100 km is more common because it shows fuel used over a fixed distance. Km per litre can also be helpful if you want a simple efficiency figure where higher means better. This calculator shows equivalent formats side by side, so you don’t need to stick to just one.