How do i work out liters per 100km?

Question

How do i work out liters per 100km?

Answer 1

100km is 100,000m

1 liter is 0.001 m³

therefore

1 liter per 100km is

(0.001m³)/(100,000m)

So, the answer is 1x10^-8 m²

Answer 2

Fill your tank. Zero your trip odometer, or record your odometer reading. Run for several days, or a long trip. Refill your tank to same level, record amount of petrol. Read trip odometer, or subtract old odometer reading from new one.

Say you took 37.0 liters to go 523 km. Divide 37 by  523, then multiply by 100.

37/523*100 = 7.07 liter/100 km.