Fuel economy converter
Enter a figure in any unit and see all four, so specs from different countries can be compared directly.
To convert MPG to km/L, multiply US MPG by 0.425144 or imperial MPG by 0.354006. To go the other way, multiply km/L by 2.352146 or 2.824809.
Why one car has three different economy figures
Three measurement systems are in common use, and they do not agree. The United States quotes miles per US gallon. The United Kingdom quotes miles per imperial gallon, which is a larger gallon and therefore a flattering number. Most of Europe quotes litres per 100 km, and much of Asia and Latin America quotes kilometers per litre.
A car rated at 30 MPG in the US is 36 MPG in Britain and 12.8 km/L in India — the same car, three numbers, none of them wrong.
The conversion factors
km/L × 2.352146 = MPG (US)
MPG (imperial) × 0.354006 = km/L
km/L × 2.824809 = MPG (imperial)
L/100km = 235.215 ÷ MPG (US)
Which unit is actually more useful
Litres per 100 km is the one that behaves sensibly when you are comparing cars. Because MPG is a ratio with distance on top, the same improvement in MPG saves wildly different amounts of fuel depending on where you start.
Going from 10 to 15 MPG saves about 78 litres over 1,000 km. Going from 30 to 35 MPG — the same five MPG — saves about 11 litres.
If you own two cars and can only improve one, improving the thirsty one is worth about seven times as much. MPG hides this; L/100km makes it obvious.
Don't know your economy yet? Work it out with the mileage calculator.
Next steps
Common questions
- How do I convert MPG to km/L?
- Multiply US MPG by 0.425144. For imperial MPG, multiply by 0.354006 instead, because an imperial gallon is larger than a US gallon.
- Why does the same car have a higher MPG in the UK?
- Because an imperial gallon is 4.54609 litres against a US gallon's 3.785411784 litres. The car travels the same distance on the same fuel, but the larger gallon produces a bigger number. 30 MPG in the US is 36 MPG in the UK.
- Is a higher or lower L/100km better?
- Lower is better. Litres per 100 km measures fuel consumed rather than distance travelled, so it runs in the opposite direction to MPG and km/L.
- What is a good fuel economy figure?
- It depends entirely on the vehicle class. Rather than chase an absolute number, compare cars of the same type in the same unit, and track your own car against its own history.