maratoolHow to convert MPG to L/100km (fuel economy)
Enter fuel economy in any unit — read US MPG, UK MPG, L/100km, and km/L side by side.
US window stickers say MPG, European specs say L/100km, and Asian markets use km/L. The MPG to L/100km Converter shows all four at once — including the often-confused UK MPG.
How it works
- Enter a value — e.g. 30 MPG or 7.8 L/100km.
- Pick its unit — the other three update instantly.
- Copy — a one-line summary of all four figures.
The inverse math
MPG and L/100km measure opposite ratios, so the conversion is a division, not a multiplication: L/100km = 235.215 ÷ MPG(US). That constant is 100 × 3.785411784 ÷ 1.609344 — exact gallon and mile definitions per fueleconomy.gov and NIST SP 811.
Because it is inverse, gains are non-linear: going from 15 to 20 MPG saves more fuel per mile than going from 40 to 50 MPG.
UK vs US MPG
An imperial gallon is 4.54609 L against the US 3.785411784 L, so UK MPG figures run 20.095% higher for identical consumption. A UK brochure claiming 50 MPG means 41.6 MPG US — or 5.65 L/100km.
Sources & methodology
Methodology reference: US EPA fueleconomy.gov. Everything runs client-side in your browser; nothing is uploaded.
More conversion guides
- How to convert liters to gallons, cups, and ounces
- How to read tire sizes and compare 205/55R16 to another size
- How to convert square feet to square meters (and any area unit)
Or browse everything at once in the new unit & sizing converters roundup.