How it’s worked out
First the fuel the journey uses, then its cost:
Litres = km × L/100 km ÷ 100 Litres = miles ÷ mpg × litres per gallon Cost = litres × price per litre
A UK gallon is 4.54609 litres and a US gallon 3.785411784, so miles per gallon means different things on each side of the Atlantic. The calculator converts between them exactly.
Worked examples
300 miles in a car doing 45 mpg (UK) uses 30.3 litres; at 1.45 a litre that is 43.95. 250 km at 6.5 L/100 km uses 16.3 litres: 23.56 at 1.45. 300 miles at 30 mpg (US) and 3.20 a US gallon costs 32.00.
How to read the result
- Fuel for the journey: the cost there, or there and back if you switch that on.
- Cost a km or a mile: handy for comparing with a train fare or claiming mileage.
- Economy: your figure in every common unit, to check against the car’s handbook.
Common mistakes
- Using US mpg for a UK car (or the other way round): the same car shows about 20% more miles per UK gallon.
- Using the official economy figure: real driving, especially fast motorway or city driving, usually uses more.
- Forgetting the way home: switch on There and back.
How to use it
- Type the distance, and switch on There and back if you’re returning.
- Choose the unit your car’s economy is in and type it.
- Type the fuel price per litre or gallon, and how many to split it between.
Questions
How do I work out the fuel cost of a journey?
Work out the fuel used from the distance and your car’s economy, then multiply by the price. 300 miles at 45 mpg (UK) is 30.3 litres, 43.95 at 1.45 a litre.
Are UK and US miles per gallon the same?
No: a UK gallon is about 20% bigger than a US gallon, so 45 mpg (UK) is about 37.5 mpg (US).
Can I split the cost between passengers?
Yes. Type how many people to split it between and it shows each person’s share.
More calculators
Elsewhere on Yuzool
- MPG to L/100 km converter in Figure
- Even Split to settle up a group trip
See all 39 calculators. Everything runs in your browser; nothing you type is sent anywhere.