Fuel Cost Calculator
Cost a journey in litres per 100 km or mpg.
Fuel cost calculator turns a distance, a fuel price and a consumption figure into the cost of the trip. Consumption is accepted as litres per 100 km, imperial or US mpg, or kilometres per litre, and shown in all four. Split it between passengers, compare two vehicles, or cost a year of commuting. Nothing is uploaded.
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Runs entirely on your device. No file or text you enter here is uploaded. How to verify it.
How to use Fuel Cost Calculator
- Enter the distance and what fuel costs where you are filling up.
- Type the consumption in whichever unit your car reports.
- Split it between passengers, or compare a second vehicle.
Questions about Fuel Cost Calculator
Is a US gallon the same as an imperial one?
No, and the difference is a fifth. An imperial gallon is 4.54609 litres and a US gallon is 3.785411784, so the same car is 30 mpg in America and 36 mpg in Britain. Comparing a figure from a US review with one from a European handbook, without converting, flatters the American car.
Why is my real economy worse than the handbook figure?
Manufacturer figures come from a standardised test cycle. Real driving is typically ten to twenty per cent worse, and considerably more in winter, in town, with a roof box or with a full car. The only economy figure that is truly yours comes from your own fill-ups: litres in, divided by distance since the last one.
Does speed really change the cost much?
Yes. Air resistance rises with the square of speed, so the same car at 80 mph uses roughly a quarter more fuel than at 65 for a journey that arrives barely any sooner. Over a long motorway trip that is real money for a few minutes saved.
How should passengers split the cost fairly?
The tool divides the fuel evenly, which is the usual starting point. Whether the driver should pay a smaller share, since they also provide the car, the tyres and the wear, is a conversation rather than arithmetic. Fuel is only part of what a journey costs the owner.
Does anything leave my device?
No. The unit conversions and the arithmetic run in the page, with no network request of any kind. Your last settings are kept in this browser so the units do not reset every time you come back.
Is Fuel Cost Calculator really free, with no limits?
Yes. There is no account, no daily cap, no file-size tier and no watermark, because there is no server cost to recover. The site is funded by clearly disclosed partner recommendations on the Partners page, never by metering the tools.
Are my files or text uploaded when I use Fuel Cost Calculator?
No. Everything is processed by JavaScript running in your browser, on your device. You can verify it: open your browser's developer tools, switch to the Network tab, and use the tool. You will see no request carrying your data — because there is nowhere for it to go.