Fuel economy converter
Convert between mpg (US), mpg (UK), L/100km and km/L.
Fuel economy converter
Convert fuel economy between mpg (US), mpg (UK/imperial), L/100km and km/L. Essential when comparing cars across countries, since the US and UK gallon differ and Europe measures consumption the other way around.
Why it’s not a simple ratio
mpg and km/L measure distance per fuel (higher is better), while L/100km measures fuel per distance (lower is better) — so they’re inversely related, not a straight multiplier. The tool converts through L/100km. Note the US gallon (3.785 L) is smaller than the UK gallon (4.546 L), so the same car shows a higher mpg in the UK.
Useful equivalents
235.215 ÷ mpg(US) = L/100km. 282.481 ÷ mpg(UK) = L/100km. 30 mpg (US) ≈ 7.84 L/100km ≈ 12.75 km/L.
Frequently asked questions
Why is UK mpg higher than US mpg for the same car? The imperial gallon is about 20% larger, so you go further per gallon.
Is lower L/100km better? Yes — it means less fuel used per 100 km.