KokoroFlow · Travel calculator
Fuel Economy Converter
Calculate your real-world fuel economy from an actual trip, convert between MPG and L/100km, or compare the annual fuel cost of two vehicles.
Calculate fuel economy
Vehicle A
Vehicle B
Frequently asked questions
How do I calculate MPG from a fill-up?
Reset your trip odometer at a fill-up, drive normally until your next fill-up, then divide the miles driven by the gallons it took to fill the tank back up. This gives a more accurate real-world number than a single tank estimate, since it accounts for a full driving cycle.
What's the difference between MPG and L/100km?
MPG (miles per gallon) is a "bigger number is better" measure common in the US, while L/100km (liters per 100 kilometers) is a "smaller number is better" measure common internationally — they measure the same underlying efficiency, just framed in opposite directions.
Why compare two vehicles by annual cost instead of just MPG?
A jump from 45 to 60 MPG saves less fuel over a year than a jump from 15 to 20 MPG, even though both are "5 MPG better" — because fuel savings scale with gallons used, not the MPG number itself. Comparing projected annual cost avoids this common misreading.