Fuel Economy Converter

Convert a fuel economy figure between km/l, miles per gallon (US and UK), and liters per 100km.

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  • Works on all devices
Enter a fuel economy value and choose the from/to units to convert between km/l, US mpg, UK mpg, and liters per 100km.

Your result

6.667

Converted value

AI explanation

Formula

Converts via km/l as a common intermediate; l/100km is handled as a reciprocal (100 ÷ km/l), since it measures consumption per distance rather than distance per fuel unit

Worked example

15 km/l to liters per 100km

Worked example: 15 km/l to liters per 100km
FieldValue
Amount15
From unitkmpl
To unitl100km
Converted value6.6667

Assumptions

  • US mpg uses the US gallon (3.785411784 liters); UK/imperial mpg uses the larger imperial gallon (4.54609 liters) — the same physical fuel efficiency gives a higher UK mpg number than US mpg.
  • l/100km is a consumption figure (lower is more efficient), the opposite direction from km/l and mpg (where higher is more efficient) — the conversion correctly reflects this inverse relationship.

Frequently asked questions

Why is l/100km a "smaller is better" unit while km/l is "bigger is better"?

l/100km measures how much fuel you consume to travel a fixed distance (so less fuel used means a smaller, better number), while km/l measures how far you travel per unit of fuel (so more distance means a bigger, better number) — they're reciprocal measures of the same efficiency.

Why do US and UK mpg figures differ for the same car?

A UK (imperial) gallon is about 20% larger than a US gallon, so the same physical fuel efficiency produces a higher mpg number under the UK convention than the US convention.

Which unit does India use for fuel efficiency?

Km/l is the standard unit used in India and most countries outside the US/UK — manufacturer spec sheets and ARAI test certifications quote mileage in km/l.

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