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MPG to L/100 km Converter

Convert fuel economy in US miles per gallon (MPG) to litres per 100 km (L/100 km).

miles per US gallon

Miles per US gallon. UK (imperial) MPG figures will give the wrong answer.

Results

Fuel consumption

7.84 L/100 km

Litres used to drive 100 km. Lower is better.

Fuel consumption: 7.84 litres per 100 kilometres.

Formula

Fuel consumption (L/100 km)
= 235.214583 ÷ US MPG

235.214583 is 100 × 3.785411784 litres per US gallon ÷ 1.609344 km per mile. MPG measures distance per fuel and L/100 km measures fuel per distance, so converting between them is a division: the higher the MPG, the lower the L/100 km.

Worked example

A US car is rated at 30 MPG. How many litres does it use per 100 km?

  1. Step 1: Convert to L/100 km

    235.214583 ÷ 30 = 7.84 L/100 km

30 US MPG is 7.84 litres per 100 kilometres.

US MPG to L/100 km table

Common fuel economy figures, rounded to two decimal places:

  • 15 MPG (US) = 15.68 L/100 km
  • 20 MPG (US) = 11.76 L/100 km
  • 25 MPG (US) = 9.41 L/100 km
  • 30 MPG (US) = 7.84 L/100 km
  • 35 MPG (US) = 6.72 L/100 km
  • 40 MPG (US) = 5.88 L/100 km
  • 50 MPG (US) = 4.7 L/100 km
  • 60 MPG (US) = 3.92 L/100 km

Only use US MPG figures

This converter expects US MPG, based on the US gallon of 3.785411784 litres. UK (imperial) MPG uses a gallon of 4.54609 litres, so UK figures are about 20% higher for the same car. Entering a UK MPG figure here would make the car look about 20% more economical than it is.

Why L/100 km is easier to compare

Fuel used is proportional to L/100 km, so it shows real savings directly. Improving from 15 to 20 MPG saves 3.92 litres every 100 km, while improving from 40 to 50 MPG saves only 1.18 litres, even though the second looks like the bigger jump.

Frequently asked questions

How do I convert MPG to L/100 km?

Divide 235.214583 by the US MPG figure. For example, 25 MPG is 235.214583 ÷ 25 = 9.41 L/100 km.

Is this US MPG or UK MPG?

US MPG: miles per US gallon (3.785411784 litres). UK MPG uses the larger imperial gallon (4.54609 litres), so the two figures are not interchangeable.

Why does a higher MPG mean a lower L/100 km?

MPG is how far a car goes on a fixed amount of fuel, so higher is better. L/100 km is how much fuel it uses to cover a fixed distance, so lower is better. One is the reciprocal of the other.

What is the 235.214583 in the formula?

It combines the unit definitions: 100 km × 3.785411784 litres per US gallon ÷ 1.609344 km per mile. Dividing it by MPG turns miles per gallon into litres per 100 km in one step.

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