Unit Converters

Fuel Economy Converter (MPG, L/100 km)

Compare car fuel efficiency between American, British and metric conventions.

By TheCalcTools Updated Formula checked and tested

Your numbers

Your results

MPG (US)
MPG (US)
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MPG (UK)
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km per liter
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Liters per 100 km
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Fuel Economy Converter (MPG, L/100 km) by TheCalcTools

How the Fuel Economy Converter (MPG, L/100 km) works

Enter a fuel-economy figure and choose its convention.

The tool converts to km per liter, then to the others.

Remember that MPG goes up with efficiency while L/100 km goes down.

The formula

L/100 km = 235.215 ÷ MPG (US)L/100 km = 282.481 ÷ MPG (UK)

Worked example

Using the default values shown in the calculator:

Fuel economy30
FromMPG (US)
  1. 30 MPG (US) = 7.84 L/100 km.
  2. That is 12.75 km per liter, or 36.03 MPG (UK).

Result:

MPG (US)30.00
MPG (UK)36.03
km per liter12.75
Liters per 100 km7.84

Frequently asked questions

Why do US and UK MPG differ?

The imperial gallon (4.546 L) is larger than the US gallon (3.785 L), so the same car has a higher UK MPG.

Which scale is better for comparing cars?

L/100 km is directly proportional to fuel used per distance, so differences are easier to read than in MPG.

Sources and further reading

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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.