Convert between MPG, km/L, L/100km and other fuel efficiency units
Fuel economy describes how efficiently a vehicle uses fuel. Depending on the country, this may be shown as miles per gallon, kilometers per liter, or liters per 100 kilometers.
Fuel economy conversions are useful when comparing cars from different countries, reading overseas reviews, planning road trips, or checking official vehicle specifications.
This fuel economy converter makes it easy to compare vehicle efficiency across different measurement systems. It is especially useful when comparing American, British, European and Japanese vehicle specifications, because each market often reports fuel use differently.
Common searches include mpg to L/100km, L/100km to mpg, km/L to mpg and US mpg to UK mpg. This page explains the main fuel consumption units and the differences between them.
There are two main ways to describe fuel use:
That is why fuel economy can seem confusing. For MPG and km/L, a larger number is better. For L/100km, a smaller number is better.
One of the most common problems is comparing US mpg with UK mpg. They are not the same, because the UK imperial gallon is larger than the US gallon.
| Unit | Meaning |
|---|---|
| 1 US gallon | 3.78541 liters |
| 1 imperial gallon | 4.54609 liters |
Because the imperial gallon is larger, the same car will usually show a higher UK mpg figure than US mpg.
| Conversion | Approximate result |
|---|---|
| 30 US mpg to L/100km | 7.84 L/100km |
| 40 US mpg to km/L | 17.00 km/L |
| 6 L/100km to US mpg | 39.20 US mpg |
| 20 km/L to US mpg | 47.04 US mpg |
| 20 km/L to UK mpg | 56.46 UK mpg |
Liters per 100 kilometers measures how much fuel a car consumes over a fixed distance. That means a lower number is better:
This is why simple mental comparison between mpg and L/100km is not always intuitive without a converter.
| Fuel economy | What it means |
|---|---|
| Higher mpg | Better efficiency |
| Higher km/L | Better efficiency |
| Lower L/100km | Better efficiency |
Because mpg and L/100km work in opposite directions, the conversion is not just a simple multiplication. This converter handles that automatically.
They are different measurement standards, not better or worse. UK mpg numbers are higher for the same vehicle because the imperial gallon is larger.
Yes. A higher km/L number means the vehicle travels farther on each liter of fuel.
For related conversions, try the Speed Converter, Length Converter and Volume Converter.