Donaldson R F MPG Converter
Convert fuel economy between UK miles per gallon, US miles per gallon, litres per 100 km and kilometres per litre.
Quick table
Why UK and US mpg are different
A UK (imperial) gallon is 4.546 litres; a US gallon is only 3.785 litres. The same car therefore has a higher mpg figure in the UK: 40 mpg UK is about 33.3 mpg US. Litres per 100 km works the other way round — a lower number means a more economical car — and is used across most of Europe. UK fuel is sold in litres but mpg is still the usual way to describe a car's economy.
Formulas: L/100 km = 282.48 ÷ mpg (UK) = 235.21 ÷ mpg (US) = 100 ÷ (km per litre). To work out what a trip costs, use the Fuel Cost Calculator.