Liters per 100 Kilometers to Miles per Gallon (US) Converter | L/100km to mpg (US)

What this converter does

European and many other car specs quote fuel economy in litres per 100 kilometres, but if you think in US miles per gallon, that figure needs turning round. This converter takes an L/100km value and gives you US mpg. Enter the L/100km and read off the mpg, so a metric economy figure lands in American terms.

The rule and its constant

The conversion is a division, because the two measures run in opposite directions:

mpg (US) = 235.215 ÷ L/100km

That constant, 235.215, carries both the unit change, litres and kilometres into US gallons and miles, and the reciprocal that flips fuel-per-distance into distance-per-fuel. It is based on the US gallon, so the result is US mpg; the same figure would give a higher number in UK mpg. Divide 235.215 by the L/100km and you have it.

Why a small L/100km gives a big mpg

It helps to expect the flip as you convert. A low L/100km figure marks an economical car, and it turns into a high mpg. A high L/100km figure, a thirsty car, turns into a low mpg. So when you put in a small L/100km number and a large mpg comes back, that is the measure turning over: little fuel for the distance is the same thing as plenty of distance for the fuel. The smaller the L/100km, the larger the mpg.

A worked example

Say a car is rated at 6 L/100km and you want that in US mpg.

• 235.215 ÷ 6 = 39.2 mpg (US)

So 6 L/100km is about 39.2 US mpg, a genuinely economical car. Reading it in mpg lets an American driver feel straight away that this is a frugal vehicle, in the unit their instinct works in.

Common L/100km values in mpg (US)

As anchors, a frugal 5 L/100km is about 47 mpg US, while a thirsty 12 L/100km is under 20 mpg US.

Where you would use it

This is for an mpg thinker reading a metric spec. European car listings, and those across many other countries, give economy in L/100km, so converting lets you judge them against the US mpg numbers you know. It helps when researching a model sold in several markets, when a review quotes L/100km, or when an imported car's figures come in the metric form. Just remember the answer is US mpg, which reads lower than the UK figure for the same L/100km.

Questions people ask

How do I convert L/100km to US mpg?

Divide 235.215 by the L/100km figure. The conversion is a division because the two measures run in opposite directions.

Is the result in US or UK mpg?

US mpg, based on the US gallon. The same L/100km figure would give a higher number in UK mpg.

What is 6 L/100km in US mpg?

About 39.2 mpg, a genuinely economical figure for a petrol car.

References

1. National Institute of Standards and Technology (NIST), Special Publication 811, Guide for the Use of the International System of Units (gallon definitions and unit conversions). https://www.nist.gov/pml/special-publication-811
2. U.S. Department of Energy and EPA, fueleconomy.gov (fuel economy ratings and fuel consumption information). https://www.fueleconomy.gov/