Fuel Economy Converter
Convert MPG, km/L and L/100km correctly.
Fuel Economy Converter
Universal unit converter engine
What does Fuel Economy Converter do?
Convert fuel consumption between miles per gallon, kilometres per litre and litres per 100 km. The last is an inverse measure, so a simple multiplication gives the wrong answer — this converter inverts properly.
How to Use Fuel Economy Converter
- 1Enter your figureFrom your dashboard or spec sheet.
- 2Select the unitCheck whether MPG is US or imperial.
- 3Read the conversionsAll measures update together.
Key Features
- US and imperial MPG kept separate — they differ by 20%
- Correct inversion for L/100km, which most simple converters get wrong
- All four measures shown at once
- Reference table for typical vehicle efficiencies
- Refuses to divide by zero with a clear message
Frequently Asked Questions
Why can I not just multiply to convert L/100km?
Because it is an inverse measure — lower is better, while higher MPG is better. You must invert as well as scale, so 8 L/100km is 29.4 US MPG, not something you can reach by a single multiplication.
Is US MPG the same as UK MPG?
No. The imperial gallon is 20% larger, so the same car rates about 20% higher in UK MPG. A 30 US MPG car is 36 imperial MPG. Comparing figures across markets without checking is a common mistake.
Which measure is most useful?
L/100km, arguably. Fuel used per fixed distance scales linearly with cost, whereas MPG does not — improving from 20 to 25 MPG saves far more fuel than improving from 40 to 45.
How do I work out my fuel cost per kilometre?
Divide L/100km by 100 and multiply by the price per litre. At 8 L/100km and £1.50 a litre, that is 12p per kilometre.
Conversions run in your browser using fixed, published factors. Nothing you enter is transmitted, and the tool keeps working with the network disconnected.
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