Fuel Cost Calculator
Work out the fuel and cost for a trip, and split it between passengers.
About this tool
Multiplies the distance by your car’s fuel consumption to get the fuel used, then by the price. Works with litres per 100 km, km per litre, and US or UK miles per gallon. Tolls, parking and wear are not included.
Before a road trip, or when friends ask to split the petrol, it helps to know what the drive will actually cost in fuel. Enter the distance, your car’s fuel economy in whichever unit you use and the price of fuel, choose one way or return, and the calculator shows the fuel needed, the total cost, the cost per kilometre or mile and each person’s share.
How to use the Fuel Cost Calculator
- Choose the unit your car’s fuel economy is quoted in.
- Enter the distance, the fuel economy and the price per litre or gallon.
- Choose one way or return, and how many people are sharing.
- Read the fuel cost, fuel used and each person’s share.
A 300 km drive at 7.5 L/100 km
A 300 km trip in a car that uses 7.5 litres per 100 km needs 300 × 7.5 ÷ 100 = 22.5 litres. At 1.80 a litre that is 40.50, or 0.135 per km. For the return trip it doubles to 45 litres and 81.00, which is 27.00 each if three people share.
Fuel economy units
Litres per 100 km, used in most of the world, measures fuel used over a fixed distance, so lower is better. Kilometres per litre and miles per gallon measure distance per unit of fuel, so higher is better. US and UK gallons differ: a UK gallon is about 4.55 litres and a US gallon about 3.79 litres, so the same car shows a higher mpg figure in the UK. Official figures are measured in tests and real driving usually uses more, especially at high speed, in traffic, with the air conditioning on or with a full load. Check your trip computer or fill-up records for a realistic number, and add a margin for detours.
Frequently asked questions
How do I work out my car’s real fuel economy?
Fill the tank, reset the trip meter, drive normally, then fill up again. Divide the litres added by the kilometres driven and multiply by 100 for L/100 km.
How do I convert mpg to L/100 km?
For US mpg, divide 235.2 by the mpg. For UK mpg, divide 282.5 by the mpg.
Does driving faster use more fuel?
Yes. Air resistance rises quickly with speed, so most cars use noticeably more fuel above about 100 km/h.
Should I include tolls?
Tolls are not included here; add them to the total before splitting the cost.