42 mpg to L/100 km
42 mpg is 5.6 L/100 km when the figure is measured in US gallons, or 6.73 L/100 km in imperial gallons. Which one applies depends entirely on where the number came from — a US window sticker and a UK brochure use the same two letters for different volumes.
- L/100 km (US)
- 5.60
- from 42 mpg US
- L/100 km (imperial)
- 6.73
- from 42 mpg imp
- km/L
- 17.86
- US basis
- mpg imperial
- 50.4
- same car as 42 mpg US
The working
US: 235.21 ÷ 42 = 5.6 L/100 km
imperial: 282.48 ÷ 42 = 6.73 L/100 km
where 235.21 = 100 × 3.785411784 ÷ 1.609344
282.48 = 100 × 4.54609 ÷ 1.609344Nearby figures
Questions
›What is 42 mpg in L/100 km?
42 mpg is 5.6 L/100 km if the figure is US, or 6.73 L/100 km if it is imperial. Divide 235.21 by the mpg for US gallons, or 282.48 for imperial.
›Is 42 mpg good?
It is around average for a modern petrol car. 5.6 L/100 km is what a mid-size saloon or small SUV typically returns on a mixed run.
›What is 42 US mpg in UK mpg?
About 50.4 mpg imperial. The imperial gallon is 20% larger, so the same car always scores higher on the UK scale — which is why the two are not interchangeable.
Want the running cost rather than the conversion? Open the fuel cost calculator.