How to use the Fuel Cost Calculator
- Enter the trip distance and its unit.
- Enter your car's fuel efficiency in L/100 km, km/L or MPG.
- Enter the fuel price per litre or gallon.
- Tick Round trip or split the cost between people if you like.
What does this tool do?
The calculator converts everything to litres per 100 km internally, so you can mix units — for example miles with a price per litre. It separates US and UK gallons, which differ by about 20%.
Why use it?
- Plan road trip budgets.
- Split fuel costs fairly with passengers.
- Handles every common efficiency unit.
Example
A 350 km trip in a car using 7.5 L/100 km needs 26.25 litres. At $1.65 per litre, that's about $43.31 one way, or $86.63 for the round trip.
The formula
Accuracy and limits
- Real fuel use depends on speed, traffic, load, weather and air conditioning. Treat the result as an estimate and add a margin.
Privacy
The calculation happens instantly in your browser. The numbers you enter are not sent to our servers or saved. There's no account to create and nothing to install.
Frequently asked questions
How do I convert mpg to litres per 100 km?
Divide 235.21 by US miles per gallon, or 282.48 by UK (imperial) miles per gallon. A car doing 30 US mpg uses about 7.8 L/100 km. The calculator does this for you when you pick your units.
How can I make the estimate more accurate?
Use your car's real fuel consumption rather than the official figure — your trip computer or a fill-up-to-fill-up calculation is best. Motorway driving at high speed, city traffic, roof boxes and cold weather can all raise consumption noticeably.
Last reviewed by the M2Toolkit team.