Fuel Consumption Converter

This free online fuel consumption conversion tool makes it easy to convert fuel efficiency values between the most commonly used metric and imperial measurement systems. Whether you’re comparing vehicle specifications, calculating running costs, or converting international fuel economy figures, this calculator provides fast and accurate results.

With this fuel consumption calculator, you can convert between Kilometres per Litre (km/L), Litres per 100 Kilometres (L/100 km), Miles per Gallon (MPG – UK/Imperial), and US Miles per Gallon (MPG – US). Simply enter a value into any of the input fields, and the tool will automatically calculate and display the equivalent fuel consumption values across all other units, helping you easily compare efficiency standards used around the world.

Enter fuel value

Kilometres per Litre

km/L

Miles per Gallon (UK)

mpg UK

Litres per 100 Kilometres

L/100 km

Miles per Gallon (US)

mpg US

Decimal places

Calculated in your browser as you type. Results are rounded only if you choose a number of decimal places.

How to use it

The fuel conversion calculator is a handy webtool to use to convert from one fuel consumption to another.

Enter a valueType a fuel figure into any one of the fields. Any number is accepted, including the ‘e’ exponent.
Read the resultsAll the other fields update automatically with the converted fuel consumption.
Copy a valueClick the clipboard button beside any field to copy it.
Tidy the numbersUse Decimal places to round the results, or leave it on full precision.

Common reference conversions

1 US gallon

Equals 3.785 litres.

1 imperial gallon

Equals 4.546 litres.

UK and US mpg

MPG (UK) is about 1.2009 × MPG (US).

Fuel consumption unit comparison table

Unit name	Symbol	Description
Kilometres per Litre	km/L	Distance travelled per litre of fuel (metric)
Litres per 100 Kilometres	L/100 km	Fuel used to travel 100 kilometres (metric standard)
Miles per Gallon (UK)	MPG (UK)	Miles travelled per imperial gallon (UK & some regions)
Miles per Gallon (US)	MPG (US)	Miles travelled per US gallon (United States standard)

Key differences to know

Lower or higher is better

Lower values are better for L/100 km, as they represent less fuel used. Higher values are better for km/L and MPG, as they represent greater efficiency.

UK and US gallons differ

UK gallons are larger than US gallons, so MPG (UK) values are always higher than MPG (US) for the same vehicle.

Who uses what

L/100 km is commonly used in Australia, Europe and many other countries.

Frequently asked questions

How do I convert L/100 km to mpg?

Divide 235.215 by the L/100 km figure to get US mpg, or divide 282.481 by it to get UK mpg. For example 8 L/100 km is about 29.4 mpg (US) or 35.3 mpg (UK).

Why do litres per 100 km and mpg move in opposite directions?

L/100 km measures fuel used for a fixed distance, so a smaller number means a more efficient car. Mpg and km/L measure distance for a fixed amount of fuel, so a larger number is better. That is why the conversion is an inverse, not a simple multiplier.

Why is a UK mpg bigger than a US mpg?

An imperial (UK) gallon is about 4.546 litres and a US gallon is about 3.785 litres, so the same car travels further per UK gallon.

What happens if I enter 0?

Zero fuel economy would mean using infinite fuel per distance (or the reverse), so the other fields are left blank.

Can I type very large or very small numbers?

Yes. Any number is accepted, including scientific notation such as 1e2.

Is anything sent to a server?

No. The conversion is calculated in your browser as you type.