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Fuel Economy Converter

Convert fuel economy between MPG, L/100km, km/L, and mi/L.

Decimal places2
  • Miles per gallon (US)
    mpg (US)
    30
  • Miles per gallon (imperial)
    mpg (imp)
    36.03
  • Litres per 100 km
    L/100km
    7.84
  • Kilometres per litre
    km/L
    12.75
  • Miles per litre
    mi/L
    7.93

How to convert fuel economy

  1. Enter a value

    Type the fuel economy figure you want to convert into the value field.

  2. Pick the source unit

    Choose the unit your value is in, such as US mpg, L/100km, or km/L.

  3. Read every conversion

    See the equivalent in all other fuel economy units update live as you type.

  4. Copy what you need

    Copy a single row or copy all conversions at once with the button below.

Why use this tool

Every unit at once

One value converts to US mpg, imperial mpg, L/100km, km/L, and mi/L simultaneously.

Handles the inverse relationship

Litres per 100 km rises as efficiency drops, while mpg and km/L rise as it improves. The tool inverts this correctly for you.

US and imperial gallons

Separate US and imperial mpg units, since an imperial gallon is larger and gives a higher mpg for the same real economy.

Copy one or all

Copy any single conversion or grab the whole list in one tap for pasting into notes or a spreadsheet.

Runs entirely on your device

Values are converted locally as you type. Nothing is uploaded or stored.

About this tool

The fuel economy converter restates a single efficiency figure across every common unit at once. Enter a value, pick its unit, and US miles per gallon, imperial miles per gallon, litres per 100 kilometres, kilometres per litre, and miles per litre all appear together.

Fuel economy is not a simple scale factor, because some units measure distance per fuel while others measure fuel per distance. Miles per gallon and kilometres per litre go up when a car gets more efficient, but litres per 100 km goes down. To handle this the tool pivots every value through litres per 100 km, inverting where needed, so a small mpg change maps to the correct L/100km figure rather than a naive multiplication.

The US and imperial gallons differ, so the same car reads as a higher number in imperial mpg than in US mpg even though nothing about the vehicle changed. Match the mpg unit to the country your figure came from. Values must be greater than zero, and any result that would be undefined shows a short hint instead of an error.

This is a unit converter for restating one economy figure in other units. It does not price a trip or estimate spend. For that, use the gas mileage calculator to work out mileage from distance and fuel, or the fuel cost calculator to estimate the cost of a journey. For plain distance conversions, try the speed converter.

Frequently asked questions

How do I convert mpg to L/100km?
Divide 235.215 by the US mpg figure to get litres per 100 km. For imperial mpg, divide 282.481 instead. This tool does it automatically and shows every unit at once.
Why is imperial mpg higher than US mpg?
An imperial gallon is about 20 percent larger than a US gallon, so the same car travels further on one imperial gallon. That makes the imperial mpg number larger even though real efficiency is unchanged.
Why does L/100km go down when mpg goes up?
They measure opposite things. Mpg and km/L are distance per fuel, so higher is better. L/100km is fuel per distance, so lower is better. The tool inverts the relationship for you.
Is this the same as a fuel cost or mileage calculator?
No. This tool only restates one economy figure in other units. To work out mileage from a fill-up or the cost of a trip, use the gas mileage calculator or the fuel cost calculator instead.
Is my input sent anywhere?
No. Every conversion happens on your device as you type. Nothing you enter is uploaded, logged, or stored.

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