Fuel Economy Converter
Convert fuel economy between US mpg, UK mpg, litres per 100 km and km per litre. Explains why higher mpg but lower L/100km is better.
mpg (UK)
36.03
L/100 km
7.84
km/L
12.75
Why this is not a simple multiplication
Miles per gallon measures distance per unit of fuel; litres per 100 km measures fuel per unit of distance. They are reciprocals, so the conversion divides rather than multiplies: L/100km = 235.215 ÷ US mpg, or 282.481 ÷ UK mpg.
US and UK gallons
A UK gallon (4.546 L) is about 20% bigger than a US gallon (3.785 L), so the same car shows a higher mpg figure in the UK. 30 US mpg is 36 UK mpg.
Frequently asked questions
What is 30 mpg in L/100km?
30 US mpg is 7.84 L/100km; 30 UK mpg is 9.42 L/100km.
Is a lower L/100km better?
Yes. It is fuel used per distance, so lower means more economical — the opposite direction to mpg.
What is 5 L/100km in mpg?
47.0 US mpg or 56.5 UK mpg.
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