Real MPG calculator

MPG stands for miles per gallon and, as this name suggests, it’s the number of miles that a car can cover on a gallon of petrol or diesel. However, the actual figure will vary dramatically depending on traffic and weather conditions, and how smoothly or aggressively the car is being driven.

What Car?’s Real MPG fuel tests are conducted on a rolling road, under strictly controlled laboratory conditions. This means our tests are repeatable, because outside variables such as weather and traffic don't affect the results. Tests are carried out at Millbrook Proving Ground, a centre used for regulatory approved vehicle emissions testing. Millbrook has the latest equipment for testing vehicles in a highly scientific manner.

Like What Car?'s Real MPG tests, the official Government tests are conducted on a rolling road, under laboratory conditions. However, these official tests don't require the engine to be worked as hard, so the resulting figures often don't reflect what you're likely to be able to achieve in the real world.

What Car?'s Real MPG figures show what you can typically expect from a car when it's driven sensibly and within speed limits, but without resorting to unusual fuel-saving measures or any 'hypermiling' techniques. Real MPG results are 4% lower on average than the latest WLTP official figures and 24% lower than the old NEDC figures which were used up until 1 September 2018.

The most efficient cars on sale today average almost 60mpg in What Car?’s Real MPG test, but anything over 50mpg is impressive.

It’s unlikely you’ll return the kind of fuel economy figures outlined in your car’s handbook or in brochures. In fact, our Real MPG testing has found that, on average, real-world economy is some 4% lower than the latest WLTP official figures - and a massive 24% lower than the old NEDC figures.

There can sometimes be a discrepancy between the economy your trip computer shows and the actual economy, too. The differences here vary from car to car.