Convert fuel economy between MPG (US/UK), L/100km and km/L.
Converted instantly in your browser.
How do you convert MPG to L/100km?
L/100km = 235.215 ÷ MPG(US) = 282.481 ÷ MPG(UK) = 100 ÷ (km/L). MPG and km/L are "higher is better", while L/100km is "lower is better", which can confuse cross-region comparisons. For example, 30 MPG (US) is about 7.84 L/100km, 36 MPG (UK) or 12.75 km/L. Lower L/100km means better efficiency.
Understanding your result
MPG and km/L are “higher is better”, while L/100km is “lower is better”, which can be confusing when comparing across regions.
Formula and method
L/100km = 235.215 ÷ MPG(US) = 282.481 ÷ MPG(UK) = 100 ÷ (km/L). Lower L/100km means better efficiency.
Assumptions and limitations
The converter changes between fuel-economy units using fixed mathematical relationships; it does not measure or predict a specific car's real-world consumption, which depends on driving conditions. It covers MPG for US and UK gallons, litres per 100 km and kilometres per litre, and assumes you know which gallon a quoted MPG figure uses before comparing.
Worked example
30 MPG (US) is about 7.84 L/100km, 36 MPG (UK) or 12.75 km/L.
How to use this tool
- Enter the value and the unit it’s in.
- Choose the unit to convert to.
- Press Convert.
About the Fuel Economy Converter
The Fuel Economy Converter switches between MPG (US and UK), litres per 100 km and kilometres per litre so you can compare cars from any market.
Who should use this tool
For car buyers and drivers comparing efficiency across markets: shoppers weighing an imported vehicle, anyone reading a spec sheet in unfamiliar units, and enthusiasts translating figures between US, UK and metric conventions. If you have a number in MPG, litres per 100 km or kilometres per litre and need it in another, this converts it.
Benefits
- Converts between US MPG, UK MPG, L/100km and km/L
- Lets you compare cars quoted in different markets
- Clarifies which direction means better efficiency
- Uses precise fixed factors for reliable conversions
Practical use cases
- Comparing an imported car's economy to local figures
- Reading a spec sheet quoted in unfamiliar units
- Converting a UK MPG rating to metric
- Checking km/L against L/100km for the same car
Explore all Travel and Vehicle tools
Frequently asked questions
Why are US and UK MPG different?
A UK (imperial) gallon is larger than a US gallon, so the same car shows a higher MPG figure in the UK than in the US.
Why can lower numbers sometimes mean a more efficient car?
It depends on the unit. With MPG and kilometres per litre, higher is better because you travel further per unit of fuel. With litres per 100 km, lower is better because you burn less fuel over the same distance. Mixing these up is a common source of confusion when comparing across regions.
Do I need to know whether an MPG figure is US or UK?
Yes, because a US gallon is smaller than a UK gallon, so the same car shows different MPG numbers in each system. Before comparing, check which gallon the quoted figure uses. The converter keeps US and UK MPG separate precisely so you can line them up correctly.