Fuel Economy Converter

Convert km/L, L/100 km, mpg (US) and mpg (UK). Results update as you type.

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About the Fuel Economy Converter

Convert fuel economy between km per litre, litres per 100 km, miles per US gallon and miles per UK gallon in one step. Enter the figure you have and see all four.

Useful when comparing cars from different countries.

The calculation runs in your browser, so the numbers you enter are not uploaded or stored.

Fuel Economy Converter example

Input

Value: 15

Output

Kilometres per litre: 15 km/L
Litres per 100 km: 6.67 L/100 km
Miles per US gallon: 35.3 mpg (US)
Miles per UK gallon: 42.4 mpg (UK)

How it is calculated

Everything is converted to km per litre and back. L/100 km is 100 divided by km/L. One US gallon is 3.785 litres, one UK gallon is 4.546 litres and one mile is 1.609 km.

km/L = 100 ÷ (L/100 km)
mpg (US) = km/L × 2.35215
mpg (UK) = km/L × 2.82481

How to use the Fuel Economy Converter

Fill in the fields above. Required fields are marked, optional ones can be left blank and fall back to the defaults described on this page.
Use “Try an example” to see a worked case, then replace the numbers with your own.
Read the results as you type. The large card is the main answer and the smaller cards are the related figures.
Copy a single value or everything, or share a link that keeps your inputs.

Fuel Economy Converter FAQ

How does the fuel economy converter work?

Everything is converted to km per litre and back. L/100 km is 100 divided by km/L. One US gallon is 3.785 litres, one UK gallon is 4.546 litres and one mile is 1.609 km.

Why is mpg (UK) higher than mpg (US)?

The UK gallon is larger, about 4.546 litres against 3.785, so the same car covers more miles per gallon on the UK scale.

Is a lower or higher number better?

Higher is better for km/L and mpg. Lower is better for L/100 km, because it measures fuel used rather than distance covered.

Is this fuel economy converter free and private?

Yes. It is free with no sign-up, and the calculation happens on your device, so your numbers are never sent to a server.

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