MPG to L/100km Converter
Enter a fuel economy figure and pick the two units. Litres per 100 km works the opposite way round to mpg and km/L, so a lower number is better there.
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Formula
mpg and km/L measure distance per volume, while L/100 km measures volume per distance, so they are reciprocals:
L/100 km = 235.2146 ÷ mpg (US)L/100 km = 282.4809 ÷ mpg (UK)L/100 km = 100 ÷ km/L
The constants come from 1 mile = 1.609344 km, 1 US gallon = 3.785411784 L and 1 UK gallon = 4.54609 L, for example 100 × 3.785411784 ÷ 1.609344 = 235.2146.
Worked example
| From | To | Calculation | Result |
|---|---|---|---|
| 30 mpg (US) | L/100 km | 235.2146 ÷ 30 | 7.840486 |
| 30 mpg (US) | km/L | 30 × 1.609344 ÷ 3.785411784 | 12.754311 |
| 8 L/100 km | mpg (US) | 235.2146 ÷ 8 | 29.401823 |
| 8 L/100 km | mpg (UK) | 282.4809 ÷ 8 | 35.310117 |
| 12.5 km/L | L/100 km | 100 ÷ 12.5 | 8 |
Frequently asked questions
How do I convert mpg to L/100 km?
Divide 235.2146 by the US mpg figure. For example 30 mpg (US) is 235.2146 ÷ 30 = 7.840486 L/100 km. For UK mpg divide 282.4809 by the figure instead.
What is the difference between US and UK mpg?
A UK (imperial) gallon is 4.54609 litres and a US gallon is 3.785411784 litres, so UK mpg figures are about 20% higher. 40 mpg (UK) is about 33.307 mpg (US).
How do I convert km/L to L/100 km?
Divide 100 by the km/L figure. A car doing 12.5 km/L uses 100 ÷ 12.5 = 8 litres per 100 km.
Why can I not convert a fuel economy of zero?
mpg and km/L are distances per volume while L/100 km is volume per distance, so one is the reciprocal of the other. Zero would need dividing by zero, which has no answer, so the converter asks for a value above zero.