Fuel economy is measured differently around the world — miles per gallon in the US and UK (using different gallon sizes), liters per 100 kilometers in most of Europe, and kilometers per liter elsewhere — which makes comparing a car spec sheet across regions confusing without a converter.
This tool converts freely between all four common representations, first converting your input to a common liters-per-100km baseline, then out to whichever unit you want.
Note that MPG and km/L express economy as distance per unit fuel (higher is better), while L/100km expresses fuel used per distance (lower is better) — the tool handles that inversion for you automatically.
Because everything runs locally in your browser, results appear instantly and nothing you type or upload is ever sent to a server.
Bookmark this page if you expect to use this tool regularly — it loads fast and behaves the same way every time, with no account needed.
This kind of task shows up constantly in everyday writing, coding, design, and admin work, which is exactly why a dedicated, focused tool saves so much back-and-forth.
A tool that does one job well, without a cluttered interface or unrelated features competing for attention, tends to be faster to use than a heavier all-in-one app.
If you find yourself needing this conversion or calculation often, keeping this page open in a tab is usually faster than digging through a bigger software suite's menus.
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Because the calculation or conversion happens instantly as you type, you can experiment freely and see how changing one value affects the result.
Many people discover a tool like this the first time they need it for a specific task, then come back to it regularly afterward once they know it exists.
Frequently asked questions
Why is the US gallon different from the UK gallon?
The US gallon and UK imperial gallon are different volumes (a US gallon is about 20% smaller), so the same MPG figure means different real-world fuel economy depending on which gallon is used.
Which unit is more intuitive?
L/100km tends to make comparing cars easier since a lower number always means better economy, while MPG and km/L require remembering that higher is better.