Gas Mileage Calculator
How it works
MPG is distance divided by fuel used — miles driven per gallon burned, so a bigger number means a more efficient car. L/100km is fuel used divided by distance, scaled to a fixed 100 km — a smaller number means a more efficient car, the opposite direction. Both describe the same fill-up; this tool computes whichever one you asked for directly from your numbers, then converts it to the other for comparison.
Frequently asked questions
How do MPG and L/100km relate?
MPG asks "how far does one unit of fuel take me?" — a bigger number is a more efficient car. L/100km asks the opposite question, "how much fuel does a fixed distance take?" — a smaller number is more efficient there. Because they measure the same efficiency from opposite directions, converting between them divides a constant by the value rather than scaling it, which is why the conversion factor (235.215) looks like an odd number at first glance.
How is this different from this site's Fuel Cost Calculator?
The Fuel Cost Calculator starts from a fuel economy figure you already know and works out what a trip will cost in money. This tool works the other way: you give it a distance you actually drove and the fuel it took, and it derives the economy figure itself — useful right after a fill-up, before you know your car's number at all.
Which figure should I trust more, MPG or L/100km?
Neither is more accurate — they describe the same fill-up. Use whichever matches how your country or car reports it; this tool shows both so you never have to convert by hand.