Fuel Economy Converter – MPG to L/100 km and km/L

How to use Fuel Economy Converter

1. Type the fuel economy figure.
2. Choose its unit, such as L/100 km.
3. Choose the unit you want, such as US mpg.
4. Read the result.
5. Compare all other units in the list.

Two opposite ways to measure

Most of Europe, Australia and Canada measure consumption: liters used per 100 km. Lower is better. The US and UK measure economy: miles driven per gallon. Higher is better. Many countries in Asia and Latin America use km per liter. Because one is the inverse of the other, you cannot convert with a simple multiplication.

L/100 km = 235.215 ÷ US mpg · L/100 km = 282.481 ÷ UK mpg

Conversion table

Why UK mpg is higher

A UK gallon (4.546 l) is about 20 % bigger than a US gallon (3.785 l), so the same car shows a higher mpg figure in Britain. Always check which gallon a review or advert uses before comparing.

The mpg illusion

Improving from 10 to 20 mpg saves far more fuel than improving from 30 to 40 mpg, even though both are +10. Over 10,000 miles the first change saves 500 gallons; the second only 83. In L/100 km the difference is obvious, which is why consumption figures are better for comparing cars.

Real-world figures

Official test figures (WLTP in Europe, EPA in the US) are usually better than what most drivers achieve. Expect 10–20 % higher consumption in city traffic, in cold weather or at motorway speeds. To turn consumption into money for a trip, use the Fuel Cost Calculator calculator.

Electric cars

Electric vehicles are rated in kWh per 100 km or miles per kWh rather than litres or gallons. In the US, the EPA also publishes an MPGe figure, which assumes 33.7 kWh of electricity equals one gallon of petrol. These numbers are useful for comparing efficiency, but the cost per kilometre depends on your local electricity and fuel prices, so compare running costs in money as well.

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