Fuel consumption is measured in units such as L/100 km, mpg (US), mpg (UK), km/L. Pick a source and target unit above, enter a value, and the result appears instantly — free and entirely in your browser. Below you'll find the most common individual conversions as dedicated pages.
Which fuel consumption units are there?
- Liters per 100 km (L/100 km) — Litres per 100 kilometres (L/100 km) is the European way to state fuel use: how much fuel a car burns over a fixed distance. Lower is better. It is a consumption figure and therefore the inverse of mpg.
- Miles per gallon (US) (mpg (US)) — Miles per gallon (US) states how far a car travels on one US gallon of 3.785411784 litres. Higher is better. Because it measures distance per fuel, it moves in the opposite direction to L/100 km.
- Miles per gallon (UK) (mpg (UK)) — Miles per gallon (UK) uses the imperial gallon of 4.54609 litres, about 20% larger than the US gallon. The same car therefore scores roughly 20% more mpg in British figures than in American ones.
- Kilometers per liter (km/L) — Kilometres per litre (km/L) is the metric economy figure used in India, Japan and much of Asia: distance covered per litre. Higher is better, and 100 divided by the L/100 km value gives it directly.
Key facts about fuel consumption
Europe states fuel use as consumption (litres per 100 km, lower is better), the US and UK as economy (miles per gallon, higher is better), and much of Asia as kilometres per litre. The two families are inverses of each other, which is why a car advert from abroad is so hard to read at a glance.
The US gallon is defined as exactly 231 cubic inches, or 3.785411784 litres; the imperial gallon is exactly 4.54609 litres (UK Weights and Measures Act 1985). That gives two different constants: mpg (US) = 235.2146 ÷ (L/100 km) and mpg (UK) = 282.4809 ÷ (L/100 km).
What can the converter not tell you?
The converter turns one figure into another; it does not measure anything. Factory values follow the WLTP test cycle and regularly sit below what a car uses on the road, and driving style, load, tyres and temperature shift the result far more than any conversion does. A value of 0 has no counterpart either: a car that burns nothing would travel infinitely far, so the field stays blank instead of showing a number.
How to use the fuel consumption converter
- Pick the source unit and enter the fuel consumption value.
- Pick the target unit — the result appears instantly.
- Use the swap button to reverse the direction.
Everything runs locally in your browser — no uploads, no waiting, no limits, and it even works offline.