Unit Converters · Science & Engineering Units
Fuel Economy Converter — km/L, L/100 km, mpg (US & UK)
Convert a vehicle's fuel economy between km/L (used in India), L/100 km (Europe and Australia), US mpg and UK (imperial) mpg. Because L/100 km measures fuel used rather than distance travelled, it's the reciprocal of the others — so this isn't a simple multiplication.
Also listed inTravel & Vehicles
Your inputs
Quick start — try a typical case
Your result Live
18 km per litre =
5.5556 litres per 100 km
- miles per gallon (US)
- 42.339
- miles per gallon (UK)
- 50.847
- miles per litre
- 11.185
How this is calculated
L/100 km = 100 ÷ km/L · km/L = mpg(US) × 0.425144 = mpg(UK) × 0.354006
- 1 US gallon
- 3.785411784 L; 1 UK gallon = 4.54609 L; 1 mile = 1.609344 km
km/L and mpg say how far you go on a fixed amount of fuel — bigger is better. L/100 km says how much fuel a fixed distance takes — smaller is better — so it's the reciprocal: 18 km/L is 100 ÷ 18 = 5.56 L/100 km. UK gallons are 20 % larger than US gallons, so the same car shows a higher mpg in the UK.
Assumptions & sources
- Exact definitions of the mile and the US and UK gallons.
- 1NIST Special Publication 811 — Guide for the Use of the International System of Units (conversion factors) — National Institute of Standards and Technology
Calculator ID UNIT-FUELECON-001 · version 1.0.0
Common questions
What is 18 km/L in L/100 km?
100 ÷ 18 = 5.56 L/100 km.
How do I convert mpg to km/L?
Multiply US mpg by 0.425144 (UK mpg by 0.354006): 30 mpg (US) = 12.75 km/L.
Why is UK mpg higher than US mpg?
A UK (imperial) gallon is 4.546 L, a US gallon 3.785 L — more fuel per gallon, so more miles per gallon.