UK MPG and fuel cost calculator
UK fuel is sold in litres, but economy is still quoted in imperial miles per gallon. Enter miles and litres, or miles, MPG and price per litre.
Estimated result
Fuel cost
Cost per mile
Imperial gallon = 4.54609 litres. US gallons are smaller — do not mix the two.
Sources
Note. These tools are indicative and do not replace DVLA, HMRC or MOT records. Check official guidance before you decide.
Frequently asked questions
Is this US or UK MPG?
UK (imperial) MPG. The same miles and litres produce a higher MPG figure than the US gallon.
Why do I still use litres?
UK pumps sell litres. The calculator converts litres to imperial gallons only for the MPG figure.
Can CarDiary track this automatically?
Yes. Log refuels in miles and litres and the app shows MPG for that combination.
