Quickly convert fuel economy units between US MPG, UK MPG, Liters per 100km, and Kilometers per Liter. Includes conversion formulas, a quick reference table, and tips for better mileage.
Fuel Economy Converter
How Fuel Economy Conversion Works
Fuel economy is measured in two ways: efficiency (how far you can go on a set amount of fuel) and consumption (how much fuel you need to cover a set distance). Because the US and the UK use different gallon sizes, "40 MPG" means something different depending on where you are.
Primary Conversion Formulas
- US MPG to UK MPG: UK MPG = US MPG × 1.201
- US MPG to L/100km: L/100km = 235.215 ÷ US MPG
- UK MPG to L/100km: L/100km = 282.481 ÷ UK MPG
- US MPG to km/L: km/L = US MPG × 0.425
Fuel Economy Quick Reference Table
A quick comparison of efficiency across major international standards:
| MPG (US) | MPG (UK) | L/100km | km/L |
|---|---|---|---|
| 15 MPG | 18.0 MPG | 15.7 | 6.4 |
| 25 MPG | 30.0 MPG | 9.4 | 10.6 |
| 35 MPG | 42.0 MPG | 6.7 | 14.9 |
| 50 MPG | 60.0 MPG | 4.7 | 21.3 |
Efficiency vs. Consumption
- MPG and km/L (Efficiency): These tell you how far you can travel per unit of fuel. Higher numbers are better.
- L/100km (Consumption): This tells you how much fuel is burned over a set distance. Lower numbers are better. This is the standard in Europe, Canada, and Australia.
The "Gallon" Confusion
A US Gallon is approximately 3.785 liters, while a UK (Imperial) Gallon is larger at approximately 4.546 liters. This is why British car reviews often show higher MPG figures than American ones for the exact same vehicle—the tank they are "measuring" with is 20% bigger.