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About the fuel economy converter
Different countries measure fuel economy in different ways:
- mpg (US) — miles per US gallon: the US
- mpg (UK) — miles per imperial gallon: the UK
- L/100 km — litres per 100 kilometres: most of Europe, Canada, Australia, China
- km/L — kilometres per litre: Japan, Korea, India, Latin America
Type a number, choose its unit and see all the others at once. Handy when comparing cars from another country, reading a foreign review, or renting a car abroad.
How to use it
- Type the fuel economy
- Choose its unit
- Read the same economy in every other unit
- Or tap one of the common values
Conversion table
| mpg (US) | L/100 km | km/L | mpg (UK) |
|---|---|---|---|
| 15 | 15.7 | 6.4 | 18.0 |
| 20 | 11.8 | 8.5 | 24.0 |
| 25 | 9.4 | 10.6 | 30.0 |
| 30 | 7.8 | 12.8 | 36.0 |
| 35 | 6.7 | 14.9 | 42.0 |
| 40 | 5.9 | 17.0 | 48.0 |
| 50 | 4.7 | 21.3 | 60.0 |
The formulas
- L/100 km = 235.21 ÷ mpg (US)
- mpg (US) = 235.21 ÷ L/100 km
- km/L = 100 ÷ L/100 km, or mpg (US) × 0.4251
- mpg (UK) = mpg (US) × 1.201
Why higher and lower both mean "better"
mpg and km/L tell you how far you go on a fixed amount of fuel — higher is better. L/100 km tells you how much fuel a fixed distance needs — lower is better. So 40 mpg (good) is 5.9 L/100 km (also good).
Frequently asked questions
What is 30 mpg in L/100 km?
7.8 L/100 km (30 US mpg). 30 UK mpg is 9.4 L/100 km.
What is 6 L/100 km in mpg?
39.2 mpg (US), or 47.1 mpg (UK), or 16.7 km/L.
Why is UK mpg higher than US mpg for the same car?
A UK (imperial) gallon is 4.546 litres, a US gallon only 3.785 litres. More fuel per gallon means more miles per gallon.
Is 5 L/100 km good?
Yes — that is about 47 US mpg, very economical for a petrol car. Most family cars use 5–8 L/100 km.
How do I work out my real fuel economy?
Fill the tank, reset the trip meter, drive normally, then fill up again. Divide the distance by the fuel you added (for km/L or mpg), or the fuel by the distance × 100 (for L/100 km).
Good to know
- Your last value is saved in this browser
- Nothing you type is sent anywhere
- To turn fuel economy into money, use the Fuel Cost Calculator
Related tools
- Fuel Cost Calculator — the cost of a trip
- Miles to km — distance conversion
- Gallons to Liters — volume conversion
- Mph to km/h — speed conversion
- Unit Converter — every unit in one place
