How Do You Calculate Fuel Consumption per Litres per 100km

Fuel consumption in litres per 100 kilometers (L/100km) is a common metric used to measure vehicle efficiency. This guide explains how to calculate it accurately and understand the results.

What is litres per 100km?

Litres per 100 kilometers (L/100km) is a measure of how much fuel a vehicle consumes to travel 100 kilometers. It's commonly used in Europe and other countries that follow the metric system. A lower number indicates better fuel efficiency.

This metric is particularly useful for comparing the fuel efficiency of different vehicles, especially when traveling long distances. It provides a direct indication of how much fuel is needed for a standard distance.

How to calculate fuel consumption

Calculating fuel consumption in L/100km requires two key pieces of information:

The total amount of fuel used (in litres)
The total distance traveled (in kilometers)

With these two values, you can determine the vehicle's fuel efficiency. The calculation is straightforward but requires careful measurement of both fuel consumption and distance traveled.

For the most accurate results, use a fuel gauge that measures to 0.1 litre precision and an odometer that shows kilometers to the nearest 1 km.

Fuel consumption formula

The basic formula for calculating fuel consumption in L/100km is:

Fuel consumption (L/100km) = (Fuel used (litres) ÷ Distance traveled (km)) × 100

This formula works by first determining the fuel consumption rate per kilometer, then scaling it up to 100 kilometers for easier comparison.

The result will be in litres per 100 kilometers, which can be interpreted as how many litres of fuel are needed to travel 100 kilometers.

Example calculation

Let's walk through an example to demonstrate how to calculate fuel consumption in L/100km.

Scenario

You fill up your car with 45 litres of fuel. After driving, you check the odometer and find you've traveled 600 kilometers.

Calculation steps

Fuel used = 45 litres
Distance traveled = 600 km
Fuel consumption = (45 ÷ 600) × 100 = 7.5 L/100km

In this example, your vehicle consumes 7.5 litres of fuel for every 100 kilometers traveled.

This calculation assumes you've used exactly 45 litres for the entire 600 km trip. In practice, you might want to measure fuel consumption over multiple fill-ups for more accurate results.

Comparison with MPG

In countries that use the imperial system, fuel efficiency is often measured in miles per gallon (MPG). To compare L/100km with MPG, you can use the following conversion formula:

MPG = 235.215 ÷ (L/100km)

For example, if your car has a fuel consumption of 7.5 L/100km, the equivalent in MPG would be:

MPG = 235.215 ÷ 7.5 ≈ 31.36 MPG

This conversion helps when comparing vehicles from different regions or when looking at specifications from different sources.

L/100km	MPG	Fuel Efficiency
5.0	47.04	Excellent
7.5	31.36	Good
10.0	23.52	Average
15.0	15.68	Poor

FAQ

Why is L/100km used instead of MPG?

L/100km is the standard fuel efficiency metric in most European countries. It provides a direct measure of fuel consumption over a standard distance, making it easier to compare vehicles. MPG is more common in the US and UK, but L/100km is often considered more intuitive for metric-based countries.

How accurate is the L/100km calculation?

The accuracy depends on how precisely you measure the fuel used and distance traveled. For the most accurate results, use a fuel gauge that measures to 0.1 litre precision and an odometer that shows kilometers to the nearest 1 km. Also, try to measure over a consistent distance for better comparison.

Can I calculate L/100km from MPG?

Yes, you can convert MPG to L/100km using the formula: L/100km = 235.215 ÷ MPG. For example, 30 MPG is approximately 7.84 L/100km. This conversion is useful when comparing vehicles from different regions.