Fuel Economy Converter
Convert between different fuel economy units including MPG, L/100km, km/L, and more.
Fuel Economy Conversion
Vehicle Fuel Economy Examples
Fuel Economy Reference Guide
Understanding Fuel Economy Units
MPG (Miles per Gallon): Distance traveled per unit of fuel
L/100km: Fuel consumed per 100 kilometers (lower is better)
km/L: Distance per liter (higher is better)
US vs UK Gallons: US gallon = 3.785L, UK gallon = 4.546L
Inverse Relationship: Higher MPG = Lower L/100km
Global Standards: Most countries use L/100km
Fuel Efficiency Categories
Excellent: 40+ MPG (5.9 L/100km or less)
Good: 30-39 MPG (6.0-7.8 L/100km)
Average: 20-29 MPG (8.1-11.8 L/100km)
Below Average: 15-19 MPG (12.4-15.7 L/100km)
Poor: Under 15 MPG (over 15.7 L/100km)
Hybrid/Electric: 50+ MPG equivalent
Conversion Quick Reference
• 30 MPG (US) ≈ 7.84 L/100km ≈ 12.75 km/L
• 40 MPG (US) ≈ 5.88 L/100km ≈ 17.01 km/L
• 50 MPG (US) ≈ 4.70 L/100km ≈ 21.26 km/L
• 6 L/100km ≈ 39.2 MPG (US) ≈ 16.67 km/L
Understanding Fuel Economy Conversions
Fuel economy is unusual because some units measure distance per fuel (miles per gallon, km per liter) while others measure fuel per distance (liters per 100 km). These are inversely related, so a higher MPG means a lower L/100km, you cannot convert them with a simple multiplier.
There is also the US-versus-imperial gallon trap: US MPG and UK MPG are different scales because the gallons differ in size, so a car rated 40 US MPG is about 48 UK MPG. When comparing vehicles across regions, always confirm which gallon and which metric the figure uses.
Frequently Asked Questions
How do I convert MPG to L/100km?
Divide 235.215 by the US MPG value. For example, 30 US MPG ≈ 7.84 L/100km.
Is lower or higher L/100km better?
Lower is better: L/100km measures how much fuel is used over a fixed distance, so a smaller number means greater efficiency.
Why is US MPG different from UK MPG?
The US gallon (3.785 L) is smaller than the imperial gallon (4.546 L), so the same car shows a higher MPG figure in the UK.
What does L/100km mean?
It is the number of liters of fuel needed to travel 100 kilometers, the standard efficiency measure in most of the world.