Fuel Economy Guide
Compare MPG, L/100km, and km/L — plus why US and UK MPG values differ
Overview
Fuel economy measures how efficiently a vehicle uses fuel. Different countries use different units, which can be confusing when comparing vehicles or reading international specifications.
The three main systems are: MPG (Miles Per Gallon) in the US/UK, km/L (Kilometers Per Liter) in parts of Asia and Latin America, and L/100km (Liters per 100 Kilometers) in Europe, Canada, and Australia.
Miles Per Gallon (MPG)
MPG - Miles Per Gallon
Used in USA and UK (with different gallon sizes!)Higher is better - More miles per gallon means better fuel efficiency.
US MPG
Uses US Gallon (3.785 L)
Most common in United States
UK MPG (Imperial)
Uses Imperial Gallon (4.546 L)
UK cars show ~20% higher MPG than US for same efficiency
Liters per 100 Kilometers (L/100km)
L/100km - Liters per 100 Kilometers
Used in Europe, Canada, Australia, and most of the worldLower is better - Fewer liters used per 100 km means better fuel efficiency.
This is essentially the inverse of MPG - it measures fuel consumption rather than distance per fuel unit.
Kilometers per Liter (km/L)
km/L - Kilometers per Liter
Used in Japan, India, parts of Latin AmericaHigher is better - More kilometers per liter means better fuel efficiency.
Similar concept to MPG but uses metric units.
Conversion Formulas
MPG (US) to L/100km
L/100km = 235.215 / MPGMPG (US) to km/L
km/L = MPG x 0.425km/L to L/100km
L/100km = 100 / km/LComparison Table
| Efficiency Level | MPG (US) | MPG (UK) | L/100km | km/L |
|---|---|---|---|---|
| Poor | 15 | 18 | 15.7 | 6.4 |
| Below Average | 20 | 24 | 11.8 | 8.5 |
| Average | 25 | 30 | 9.4 | 10.6 |
| Good | 35 | 42 | 6.7 | 14.9 |
| Excellent | 50 | 60 | 4.7 | 21.3 |