WLTP Explained

WLTP stands for worldwide harmonised light vehicle test procedure and is a new way of measuring a vehicle's emissions and fuel consumption. It replaces the old NEDC test which was found to be obsolete and inaccurate as it relied on too much on perfect laboratory conditions and did not reflect the real-world performance of a vehicle.

Why is the WLTP needed?

The faults of the old NEDC tests means that vehicles produced more harmful emissions and used more fuel than what they actually did when used in the real world, on real roads and by real drivers. This means that the car you drove did not perform as stated in the test and never would.

The NEDC tested vehicles in laboratory settings and did not consider variable driving styles and speeds and the test itself was quite short. Simply put, you would never be able to replicate the NEDC test on the road therefore the figures were almost irrelevant to a point. Critics of the NEDC which included the Financial Times concluded it just wasn't good enough for the modern world where emissions and fuel consumption were a hot topic, they even go on to say that the WLTP still falls short.

In essence, vehicles were polluting more than the average person knew. When you consider the 40 million or so cars on the road in the UK this is a significant amount of emissions being pumped into the air than first thought and degraded the air quality significantly.

NEDC was simply not fit for purpose and new emissions and consumption test needed to be created - The WLTP.

How is the WLTP different to NEDC?

The WLTP test is significantly different from NEDC and much more thorough.


  • WLTP has a dynamic cycle of testing and not just one
  • The test time is increased from 20 minutes to 30 minutes
  • The vehicle will be tested over 14.4 miles up from 6.8
  • Driving phrases increased from 2 to 4 to cover urban, non-urban and a mix of the two for a better representation of all journey types
  • The average speed of the vehicle being tested is now 29 mph from 21 mph and the maximum speed tested is now 81 mph up from 75 mph.
  • The vehicle will now have its optional equipment tested when it did not in the past. These can include the infotainment system, climate control/air con and lights.


When did the WLTP come into use?

Development of the WLTP standard began in 2017, started being used in 2018 and enforced in 2019. This means that every car you buy brand new will have been through the WLTP tests with their information available along with the old NEDC (at least for now).

What are the benefits of the WLTP test?

The clear benefit and the goal of the WLTP is a more accurate calculation of a vehicle's performance, specifically the emissions and fuel consumption ratings. For the end-user, you will get a car that closely resembles what you read in brochures and fewer surprises when you notice you can only get 30 mpg when the brochure said it was 50 mpg, however they still won't be 100% accurate and may never be due to individual driving styles and journeys.

WLTP forces manufacturers to make their vehicles more efficient to pass the test and the user benefits from this change being brought forward. But, the cost of vehicles will have increased slightly to make up the difference.

What does the WLTP change for leasers?

Because WLTP has now been adopted as of April 2020, your experience is unlikely to change and most vehicles on our website will have their WLTP test results. Road Tax changes are now in full effect and will not change again for the foreseeable.

However, you may find your current vehicle is now more expensive than it used to be because of the test and everything a manufacturer has to do to pass that test. If you desired to replace a vehicle like for like then it's more likely than not to be more expensive now. Plus, the vehicle you used to have is probably not even in production because of WLTP.

All the painful industry changes have already been and gone and the bumpy ride is over. It's fair to say the manufacturers themselves faced the biggest brunt of the WLTP as they had to make fundamental changes in the way their engines work to comply with the WLTP.