Free online fuel economy converter

Fuel efficiency is measured differently around the world — MPG in the US and UK, L/100km in Europe, and km/L in Asia. This converter shows all five common units at once.

Value

From

How to use

Enter a fuel economy value.
Select the unit you are converting from.
Select the unit you want to convert to.
The result and a full conversion table appear instantly.
Click “Share with my numbers” to copy a URL with your inputs.

Conversion formulas

All conversions use L/100km as the internal reference:

From	To L/100km
MPG (US)	235.215 ÷ mpg
MPG (UK)	282.481 ÷ mpg_uk
km/L	100 ÷ kml
L/100km	(no change)
L/100mi	value × 100 ÷ 160.934

Worked example

30 MPG (US) converted:

L/100km = 235.215 ÷ 30 = 7.84 L/100km
MPG (UK) = 282.481 ÷ 7.84 = 36.03 MPG UK
km/L = 100 ÷ 7.84 = 12.76 km/L

Notes

Constants: 1 US gallon = 3.785411784 L; 1 UK gallon = 4.54609 L; 1 mile = 1.609344 km.
Source: US EPA fuel economy methodology; Wikipedia “Fuel efficiency” (https://en.wikipedia.org/wiki/Fuel_efficiency).
L/100km and L/100mi use an inverse relationship to distance — lower is more efficient.

References

Fuel economy in automobiles — MPG, L/100km and conversionsWikipedia · en.wikipedia.org
How Vehicles Are Tested — official EPA/DOE fuel economy methodU.S. DOE / EPA (FuelEconomy.gov) · fueleconomy.gov

Frequently asked

How do you convert MPG to L/100km?

Divide 235.21 by the MPG value. Example: 30 MPG = 235.21 ÷ 30 ≈ 7.84 L/100km.

How do US MPG and UK MPG differ?

The UK gallon (imperial gallon) is larger than the US gallon — 4.546 L vs 3.785 L. So 1 UK MPG ≈ 1.2009 US MPG. A car rated 40 MPG UK is about 33 MPG US.

Is a higher or lower L/100km better?

Lower is better for L/100km and L/100mi — they measure how much fuel you use per distance. Higher is better for MPG and km/L — they measure how far you go per unit of fuel.

What is km/L?

Kilometers per liter (km/L) is used in Japan, India, and some other countries. It is mathematically equivalent to MPG but using metric units. 1 km/L ≈ 2.352 US MPG.

What is the formula for L/100km to MPG?

MPG = 235.215 ÷ L/100km. Example: 8 L/100km = 235.215 ÷ 8 ≈ 29.4 MPG (US).

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