MPG calculator

MPG is miles divided by gallons. Two hundred and fifty miles on six imperial gallons is 41.7 MPG, equal to 34.7 US MPG or 6.78 litres per 100 km. Always check which gallon a quoted figure uses before comparing.

MPG is a rate with an awkward property: it is inversely proportional to fuel used, so equal improvements in MPG are not equal savings. Going from 15 to 20 MPG saves more fuel over the same distance than going from 40 to 60. That is why fuel-consumption labelling in most of the world uses litres per hundred kilometres, and why comparing two cars purely on MPG can push you toward the wrong one. The tool prints both so the comparison is available either way.