Kilometers per Liter to Liters per 100 Kilometers Converter | km/L to L/100km

What this converter does

Kilometres per litre and litres per 100 kilometres both describe fuel economy, but they look at it from opposite ends. This converter takes a figure in km/L and turns it into L/100km, the measure used across Europe and much of the world. Enter the km/L value and read off the L/100km.

The flip: distance per fuel, fuel per distance

This is the thing to understand before anything else. Kilometres per litre measures distance per unit of fuel, so a higher number is better. Litres per 100 kilometres measures fuel per unit of distance, so a lower number is better. They run in opposite directions. As a car gets more efficient, its km/L rises while its L/100km falls. So you are not just changing units here, you are turning the measure inside out, from how far you go on the fuel to how much fuel the distance costs.

The rule: 100 divided by the figure

Because the two are reciprocals scaled to 100 kilometres, the conversion is a division rather than a multiplication:

L/100km = 100 ÷ km/L

You divide 100 by the km/L figure. That is all there is to it, and the neat part is that the same rule works in reverse too, since dividing 100 by an L/100km figure gives you back the km/L. One simple operation, going both ways.

A worked example

Say a car manages 20 km/L and you want that as litres per 100 km.

• 100 ÷ 20 = 5 L/100km

So 20 km/L is 5 L/100km. Read it out loud and it makes sense: a car that travels 20 km on a litre needs 5 litres to cover 100 km. The high km/L and the low L/100km are describing the same efficient car, just from the two different directions.

Common km/L values in L/100km

Notice the columns move in opposite directions: as km/L climbs, L/100km falls, exactly as the flip in meaning would lead you to expect.

The point where they meet

There is one tidy coincidence worth knowing. At 10 km/L, the L/100km figure is also 10, because 100 divided by 10 is 10. It is the single point where the two measures give the same number. Above 10 km/L, the L/100km figure drops below the km/L one; below it, the L/100km figure climbs higher. It is a handy mental marker for telling at a glance which side of average a car sits on.

Questions people ask

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

Divide 100 by the km/L figure. The two measures are reciprocals, so the conversion is a division, not a multiplication.

Why does a higher km/L give a lower L/100km?

Because they measure opposite things. Kilometres per litre is distance per fuel, where higher is better, while litres per 100 km is fuel per distance, where lower is better. As one rises, the other falls.

What is 20 km/L in L/100km?

5 L/100km. A car going 20 km on a litre uses 5 litres to cover 100 km.

References

1. National Institute of Standards and Technology (NIST), Special Publication 811, Guide for the Use of the International System of Units (unit conversions). https://www.nist.gov/pml/special-publication-811