How will the new CO2 calculation method impact your car?

There is a new method for calculating CO2: The old test, used only in Europe – the New European Driving Cycle (NEDC) – has been replaced by a new worldwide test: the Worldwide Harmonised Light Vehicle Test Procedure (WLTP). There is no fiscal impact yet as a transition period is currently in place.

How will the new CO2 calculation method impact your car?


From September 2018 onwards, all registered cars will be subject to a new European regulation which will ensure that emissions, namely particulate matter and nitrogen oxides, are more strictly measured. This new WLTP test will replace the existing NEDC test.

The WLTP test ensures an average increase of 5 g of CO2/per kilometre. As the CO2 value increases, so does the amount of Belgian car tax – particularly vehicle registration tax (BIV) and road tax.

The table below clearly illustrates this increase based on some practical examples:

Transition period

In order to bring about the gradual transition from the current NEDC values to the new WLTP values, a transition period is being put in place which will continue until the end of 2019 in Flanders and until the end of 2020 in Wallonia. A method was developed to calculate an NEDC CO2 value using the WLTP CO2 value measured during this phase. For now, the old measuring method is still being used for taxation purposes: the NEDC test. For this reason, no fiscal impact is being felt yet.

Consequences for new and old vehicles

If you still have a vehicle that was registered before September 2018, the CO2 value from the time of registration remains valid. Therefore, only the NEDC value is stated on your European certificate of conformity.

Today, if you purchase a new car, both the NEDC and WLTP values will be stated on your European certificate of conformity.

Tax will, therefore, continue to be calculated based on the NEDC value across Flanders until the end of 2019. The new government will have to decide how long the old test values can continue to apply and how to deal with the fiscal impact of the new values.

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