⛽ Fuel Economy Converter
Convert between miles per gallon (MPG), liters per 100km and kilometers per liter.
Buying a car from another country? Planning a road trip across borders? Comparing fuel efficiency specs between US and European vehicles can be surprisingly confusing. Our Fuel Economy Converter makes it easy to switch between miles per gallon (MPG), liters per 100 kilometers (L/100km), and kilometers per liter (km/L).
Let’s say you’re shopping for a European hatchback that lists fuel consumption as 5.5 L/100km, but you’re used to thinking in MPG. Enter 5.5 in the value field, select L/100km as “From” and MPG as “To” — the result shows 5.5 L/100km = 42.77 MPG. Now you can meaningfully compare that car’s efficiency against the US-market vehicles you’re already familiar with.
This converter is essential for several real-world situations. Car buyers use it to compare fuel economy across different measurement systems when considering imports. Road trippers converting between the US and Canada or Europe find it invaluable for fuel budgeting — knowing how many liters you’ll need for a 500 km drive given your car’s MPG rating. Fleet managers use it to normalize fuel cost calculations across vehicles with different efficiency standards.
The conversion factors are based on the standard formula: 1 MPG = 235.214 L/100km (or equivalently 1 L/100km = 235.214 / MPG). The converter handles all the math internally, giving you clean, rounded results to 2 decimal places — all the precision you need for trip planning, car comparisons, or fuel budget estimates.
Frequently Asked Questions
What's the difference between US MPG and UK MPG?
This converter uses US MPG (based on the US gallon of 3.785 liters). UK MPG uses the Imperial gallon of 4.546 liters, so UK MPG figures are about 20% higher even for the same vehicle. If you need UK MPG, you can convert US MPG by multiplying by 1.201.
When would I use km/L vs L/100km?
km/L is the inverse of L/100km — it tells you how many kilometers you can drive per liter of fuel. It's used in parts of Asia, Africa, and Latin America. L/100km is standard in Europe, Canada, and Australia and indicates how many liters are needed to travel 100 km. The higher the km/L, the better; the lower the L/100km, the better.
Why can't I enter 0 into the converter?
Fuel economy conversion involves division (e.g., 235.214 / MPG), so a value of 0 would result in an undefined calculation. Because of this, the tool displays a helpful message asking you to enter a value greater than 0.
How accurate is the conversion factor 235.214?
The factor 235.214 is the standard conversion constant between US MPG and L/100km, derived from 1 US gallon = 3.785411784 liters and 1 mile = 1.609344 km. It's accurate to three decimal places, which is more than sufficient for fuel economy comparisons and trip planning.