Skip advert
Advertisement

Gap between official and real-world fuel economy grows to 42 per cent

Fresh research reveals average gap between quoted and real-world fuel consumption has risen from nine per cent in 2001 to 42 per cent today

real world and official fuel economy gap grows

The average gap between a car’s official fuel economy figures and those obtained in real-world driving conditions has leapt to 42 per cent, new research has found. 

The International Council on Clean Transportation (ICCT) analysed data from over a million vehicles in eight European countries, including the UK, to reach its findings. The latest 42 per cent discrepancy follows 2013 data that found a 25 per cent average gap between advertised and real-world economy in 2013; back in 2001, the discrepancy was just nine per cent. 

Advertisement - Article continues below

Privately-owned cars fared slightly better than company cars, with the former posting an average 39 per cent discrepancy and the latter a 45 per cent difference between official and achieved economy. The ICCT estimates consumers pay £350 extra a year for fuel as a result of these differences. 

These figures may well improve in the future, however, thanks to the introduction of a new WLTP testing procedure for economy and emissions. This new regime was introduced in September 2017 and will become mandatory for all new cars from September 2018. The WLTP procedure replaces the outgoing NEDC assessment programme, which saw cars tested for just 20 minutes in order to ascertain emissions and fuel economy. 

Despite the new testing regime, the ICCT says more may need to be done to address the cap between official and reported economy, as the new WLTP programme: “contains new loopholes that could permit the performance gap to increase again.”

Do you think a 42 per cent difference between quoted and real-world fuel economy figures is acceptable? Let us know below...

Skip advert
Advertisement
Skip advert
Advertisement

Most Popular

Maybe I’m just getting old, but modern cars should be less complex to drive
Opinion - Paul Barker driving the Polestar 3

Maybe I’m just getting old, but modern cars should be less complex to drive

Editor Paul Barker wants his car to act more like a car, and less like a smartphone
Opinion
1 Apr 2026
Best car engines of all time
Best car engines - header image

Best car engines of all time

What makes a great internal-combustion motor? We explain why these petrols, diesels and even a hybrid made the list
Features
3 Apr 2026
Motability to force black box trackers on all drivers under 30
Wheelchair user plugging a charging cable into a Vauxhall Astra Electric

Motability to force black box trackers on all drivers under 30

The Motability Scheme, which provides cars for disabled drivers, has faced new changes after Government tax hikes
News
2 Apr 2026

Find a car with the experts