Fuel Economy Converter
Convert fuel economy between miles per gallon (US and UK), kilometers per liter and liters per 100 km.
Change the values and press Calculate to work out your own figures.
Enter a fuel economy, choose its unit and the unit you want. The answer is exact until it is shown, and the same value appears in every other unit.
Show the working
- 30 mpg = 12.7543112229 km/L
- 12.7543112229 km/L = 7.84048611111 L/100 km
How to use it
Type a fuel economy, choose the unit it is in and the unit you want, then press Calculate. You can type decimals, fractions such as 3/8, mixed numbers such as 1 1/2, very large or small numbers such as 2.5e6, and simple sums such as 2*3. Swap exchanges the two units.
The answer is worked out with exact fractions and only rounded for display, to 12 significant figures. Below it you get the same value in every other unit on the list, and Show the working gives the factor that was used.
Key definitions
L/100 km = 100 ÷ (km/L) L/100 km ≈ 235.215 ÷ mpg (US) 1 mpg (UK) ≈ 0.832674 mpg (US)
Which way round?
Miles per gallon and kilometers per liter measure distance per fuel, so higher is better. Liters per 100 km measures fuel per distance, so lower is better. Converting between them is a division, not a multiplication: 30 mpg (US) is about 7.84 L/100 km.
US and UK gallons
A UK (imperial) gallon is about 20% larger than a US gallon, so the same car shows a higher mpg figure in the UK. 30 mpg in the US is about 36 mpg in the UK.
Questions
What is 30 mpg in L/100 km?
About 7.84 L/100 km (US gallons).
Why is UK mpg higher than US mpg for the same car?
Because the UK gallon is bigger: 4.546 litres against 3.785.
Formulas
result = (value × f(from) + o(from) − o(to)) ÷ f(to)
Sources
Limitations
- Only the units listed are supported here; other fuel-economy units arrive with later M4 slices.