mi/L to km/L — convert miles per litre to kilometres per litre

One mile per litre is 1.609344 kilometres per litre.

1 mile per litre is 1.609344 kilometres per litre. The working is 1 mi/L → 1.609344 km/L.

Because the two measures run in opposite directions. Miles per gallon counts distance per unit of fuel; litres per 100 km counts fuel per unit of distance. One is the reciprocal of the other, so you divide rather than multiply.

The Imperial gallon is about 20% larger, so the same car travels further on one of them. A car rated 30 mpg in the US is around 36 mpg in the UK, with nothing about the car having changed.

The first, by a wide margin. Over 10,000 miles the 15-to-20 change saves about 167 gallons; the 30-to-40 change saves about 83. This is exactly the trap the inverse relationship sets, and why litres per 100 km is the easier measure to reason with.