Enter a fuel-economy figure, pick the unit you have and the unit you want, and read the result instantly — plus the value in every other unit at once. It converts between litres per 100 km (how consumption is quoted here), km per litre, and miles per gallon in both the US and UK definitions. Everything runs in your browser.
In all units
- Litres per 100 km (L/100km)1 L/100km
- Kilometres per litre (km/L)100 km/L
- Miles per gallon (US)235.214583 mpg US
- Miles per gallon (UK)282.480936 mpg UK
How it works
Fuel economy is reciprocal, not linear: L/100km measures fuel used over a fixed distance, while mpg and km/L measure distance covered per unit of fuel. So a smaller L/100km is better, but a larger mpg is better. Converting between them means dividing rather than multiplying — km/L is 100 ÷ (L/100km), and the tool handles this inversion for you.
The two miles-per-gallon figures are different because the gallons are different: a US gallon is 3.785 litres and an imperial (UK) gallon is 4.546 litres. The same "30 mpg" therefore means less fuel burned if it is UK mpg. The conversions use 100 km = 62.137 miles, so L/100km → US mpg is 235.215 ÷ L and → UK mpg is 282.481 ÷ L.
Practical examples
A car rated in L/100km to US mpg
A car using 8 L/100km does about 29.4 US mpg. Enter 8, from L/100km, to US mpg — useful when reading an American review of a European model.
US mpg back to L/100km
A "35 mpg (US)" rating is about 6.72 L/100km. Convert US mpg to L/100km to compare a US spec sheet with local figures.
US vs UK mpg for the same car
6 L/100km is 39.2 US mpg but 47.1 UK mpg — same car, two scales. The all-units list shows both at once so an mpg number is never ambiguous.
Frequently asked questions
How do I convert L/100km to mpg?
Divide 235.215 by the L/100km figure for US mpg, or 282.481 for UK mpg. For example 7 L/100km is about 33.6 US mpg. The relationship is reciprocal, so the tool divides rather than scales — just pick the units.
Why are US mpg and UK mpg different?
Because the gallon is different. A US gallon is 3.785 litres; a UK (imperial) gallon is 4.546 litres, about 20% larger. So a UK mpg number is always higher than the US number for the same real economy. Always note which one a figure uses.
Is a higher or lower number better?
For L/100km, lower is better — you burn less fuel over the same distance. For mpg and km/L, higher is better — you travel further on the same fuel. That flip is exactly why a converter helps.
What is km/L and where is it used?
Kilometres per litre is distance travelled on one litre; 20 km/L means 5 L/100km. It is common in parts of Asia and useful for a quick "how far per litre" sense. One divided into the other converts between km/L and L/100km.
How do I convert km/L to L/100km?
Divide 100 by the km/L value: 18 km/L is about 5.56 L/100km. Enter km/L and read the L/100km row — the two are exact reciprocals scaled by 100.
What counts as good fuel economy?
As a rough guide, a modern petrol car around 5–7 L/100km (34–47 US mpg) is efficient, while over 10 L/100km (under 24 US mpg) is thirsty. Real figures depend on driving style, load and conditions — treat any single number as a comparison point, not a promise.
Does it accept the decimal comma?
Yes. You can type 6,5 or 6.5 and both mean six and a half. This matters because consumption here is usually written with a comma, like 5,8 L/100km.
What happens if I enter zero?
Zero has no meaningful reciprocal (you cannot cover distance on no fuel, or use no fuel over a distance), so the converted value shows a dash. Enter a positive figure to get a result.
Are the values I enter sent anywhere?
No. The conversion runs entirely in your browser; nothing is uploaded and analytics never receives the numbers.
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