MPG to L/100km Converter

Convert the other wayL/100km to MPG

Enter an MPG figure and which gallon it used to see litres per 100 km. Useful when a US or UK brochure needs a European consumption number.

How it works

The identity is the inverse of L/100 km → MPG, with the same constants: 1.609344 km per mile, 3.785411784 L per US gallon, 4.54609 L per Imperial gallon. 30 US MPG is about 7.84 L/100 km; 30 Imperial MPG is about 9.42 L/100 km. If you treat a US window-sticker MPG as Imperial, the metric result will be too thirsty.

Formula

L/100 km = (100 × litres per gallon) ÷ (MPG × 1.609344 km/mile)

Worked examples

30 US MPG → 7.84 L/100 km
30 Imperial MPG → 9.42 L/100 km

Useful notes

Select the gallon that the MPG figure was measured with.
Zero MPG is undefined (infinite consumption) and is rejected.

FAQ

My car says 30 mpg. Which gallon is that?: In the United States it is almost always the US liquid gallon. Older UK figures often used the Imperial gallon. If unsure, convert both and compare to the handbook’s L/100 km.
Does a higher MPG mean lower L/100 km?: Yes, for the same gallon standard. They move in opposite directions.
Can I use this for trip fuel?: Convert to L/100 km first, then use the Fuel Cost calculator with kilometres.

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