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30 mpg to L/100 km

30 mpg is 7.84 L/100 km when the figure is measured in US gallons, or 9.42 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)
7.84
from 30 mpg US
L/100 km (imperial)
9.42
from 30 mpg imp
km/L
12.75
US basis
mpg imperial
36.0
same car as 30 mpg US

The working

US:        235.21 ÷ 30 = 7.84 L/100 km
imperial:  282.48 ÷ 30 = 9.42 L/100 km

where 235.21 = 100 × 3.785411784 ÷ 1.609344
      282.48 = 100 × 4.54609    ÷ 1.609344

Nearby figures

Questions

What is 30 mpg in L/100 km?

30 mpg is 7.84 L/100 km if the figure is US, or 9.42 L/100 km if it is imperial. Divide 235.21 by the mpg for US gallons, or 282.48 for imperial.

Is 30 mpg good?

It is around average for a modern petrol car. 7.8 L/100 km is what a mid-size saloon or small SUV typically returns on a mixed run.

What is 30 US mpg in UK mpg?

About 36 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.