Fuel Consumption & MPG Calculator
Measure fuel economy, compare units and estimate annual fuel cost
Measure real-world fuel economy
Fill the tank, reset the trip meter, then record the distance and fuel added at the next complete fill-up. Measuring several tanks reduces the effect of one uneven fill.
Read the units correctly
A lower L/100 km figure is more efficient. A higher km/L or MPG figure is more efficient. US and Imperial MPG are not interchangeable because the gallons have different volumes.
Treat cost as a scenario
Fuel price and annual distance are your assumptions. The calculator does not fetch current fuel prices. Driving style, traffic, weather, load and tires affect actual consumption.
Frequently Asked Questions
How do I calculate L/100 km?
Divide liters used by kilometers driven, then multiply the result by 100.
What is the difference between km/L and L/100 km?
km/L shows distance per liter, while L/100 km shows fuel used for 100 kilometers. Their scales run in opposite directions.
How do I convert MPG to L/100 km?
The calculator converts distance and fuel into common base units, then displays both measures.
Are US and Imperial gallons the same?
No. An Imperial gallon is larger than a US gallon, so the same fuel economy produces different MPG figures.
Why can the dashboard reading differ?
Fill level, measurement period, temperature and rounding can make tank records differ from the vehicle display.
How can I get a reliable measurement?
Measure several complete fill-ups and use a consistent pump shutoff point.