Fuel Economy Converter

Same value in every unit

UnitValue

What this converter does

Enter a number, pick the two units and the answer appears as you type. The table underneath shows the same value in km/L, mpg and L/100km and every other unit on the list, so comparing them takes one glance rather than several conversions. Nothing is sent anywhere.

Conversion factors used

  • 1 km/L = about 2.352 US mpg
  • 1 US gallon = 3.785411784 L — the UK gallon is 4.54609 L, so UK mpg reads higher
  • L/100km = falls as efficiency rises, so it is the inverse of the others
  • 20 km/L = the same as 5 L/100km

Tips

  • Use Swap to reverse the direction without retyping the number.
  • Very large and very small results switch to scientific notation so they stay readable.
  • The result box is read-only — use Copy result to take the number.

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Free to use, no sign-up, works on any phone.

Frequently Asked Questions

Is this converter accurate?

Yes. Every factor is the exact defined value rather than a rounded one, and results are only rounded when they are displayed. Where a unit has no single agreed value it is left out instead of guessed at.

Does my data get uploaded?

No. The conversion is arithmetic done by JavaScript inside your browser, so the numbers you type never leave your device and the tool keeps working offline once the page has loaded.

Why does the answer switch to something like 1.23e-9?

That is scientific notation, used when a result is very large or very small. Writing it out in full would run to dozens of zeros and be harder to read, not easier.

Can I see every unit at once?

Yes — the table below the result shows your value in every supported unit at the same time, which is quicker than converting once for each one.

Everything on this page runs inside your own browser. Nothing you type or upload is sent to a server, so your data never leaves your device.