Fuel Economy Converter
Convert between MPG, L/100km, and km/L.
Enter your values to calculate your result.
Formula
MPG and km/L measure how far you travel per unit of fuel (higher is better), while L/100km measures how much fuel you use per fixed distance (lower is better) — converting between them involves an inversion, not just a ratio.
Frequently Asked Questions
Why does a smaller L/100km number mean better efficiency, while a bigger MPG number does too?
They measure efficiency in opposite directions: L/100km is fuel used per distance (less is better), while MPG is distance per unit of fuel (more is better).
Is a US MPG the same as a UK MPG?
No — a US gallon and a UK (imperial) gallon are different sizes, so the same real fuel economy gives a different MPG number depending on which gallon is used. This calculator keeps them as separate units.