Convert fuel economy between US MPG, UK MPG, and metric liters per 100 km — the inverse relationship that trips up many drivers comparing cars across regions.
How it works
- Enter your vehicle's fuel rating.
- Select whether it is stated in US MPG, UK MPG, or L/100km.
- The calculator determines the inverse metrics to show the exact equivalent in other regions.
Frequently asked questions
Why is the relationship inverse?
MPG measures distance per unit of fuel; L/100km measures fuel per fixed distance. As one rises, the other falls — they are reciprocals.
Why do US and UK MPG differ?
The UK gallon is about 20% larger than the US gallon, so the same efficiency shows a higher number in UK MPG.
What is a good L/100km?
Lower is better. Efficient cars often sit around 5 to 7 L/100km, roughly 34 to 47 US MPG.