myFuel Economy Converter
Convert MPG, L/100km and km/L instantly. Calculate cost per 100 km.
Enter a value in any field — all others update instantly.
About the Fuel Economy Converter
Units of fuel economy
Fuel economy is measured differently around the world. The UK and US use miles per gallon (mpg), though US and UK gallons differ in size. Most of Europe and Asia use litres per 100 km (L/100km). Lower L/100km means better efficiency; higher mpg means better efficiency.
How to use it
Enter a value in any unit and the other three update instantly. Switch between units to compare vehicles rated in different regional standards.
- UK mpg → L/100km — divide 282.5 by the mpg figure
- US mpg → L/100km — divide 235.2 by the mpg figure
- UK vs US gallon — 1 UK gallon = 1.201 US gallons, so UK mpg figures are always higher
How to improve real-world fuel economy
Manufacturer fuel economy figures are obtained under controlled test conditions and rarely match real-world driving. Factors that most significantly improve real-world economy: maintaining steady speed on motorways (cruise control if available), keeping tyres at correct pressure, removing roof boxes and bike racks when not needed, and anticipating traffic to avoid unnecessary braking and acceleration.
- Tyre pressure — under-inflation by 10 PSI increases fuel use by 1-2%; check monthly
- Speed — the largest variable; driving at 60 mph instead of 80 mph saves 20-25% fuel
- Aerodynamic drag — a roof box can increase fuel consumption by 10-20%; remove when not in use
- Smooth driving — anticipating stops and coasting to a halt avoids wasted kinetic energy