Calculating Vehicle Registration Tax

Nitrogen Oxide emissions


From 1 January 2020 a second component will be added to the calculation of vehicle registration tax. The Nitrogen Oxide (NOx) charge will be combined with the existing Carbon Dioxide rates to form the VRT payable. 

More information on how this will be calculated can be found in Calculating the Nitrogen Oxide Charge.


The NOx levy will be chargeable on all Category A vehicles registered after 31 December 2019. Customers registering a vehicle after this date will have to provide evidence of the vehicles NOx emissions to finalise registration. 

Failure to provide this information may lead to delays or a flat charge being imposed, see Calculating the Nitrogen Oxide Charge. There are a number of sources where the emissions figure may be obtained which are outlined below.  

New Vehicles

For new vehicles the amount of NOx emissions is recorded on the vehicles Certificate of Conformity. This document should be obtained from the seller or from the vehicles manufacturer.  

A Certificate of Conformity is required to be uploaded in advance of a vehicles registration inspection. A manual on uploading an eCOC is available to assist customers.

Used Vehicles

The foreign registration certificate (FRC), which is a mandatory document for all used vehicles, may contain a NOx emissions figure.   

United Kingdom imports may have the NOx figure on the FRC if the document was issued prior to April 2019. This is usually displayed in box V3 of the V5 the UK registration certificate.

If not present on the foreign registration certificate, customers are advised to obtain the Certificate of Conformity for the vehicle. This can be obtained by contacting a main dealer or the manufacturer directly.

Revenue will also accept official written confirmation from the manufacturer or an appropriate statutory authority of the NOx emissions. These will be considered on a case by case basis depending on the documentation presented.

A NOx figure for Japanese imports can be obtained from the Japanese Ministry of Land, Infrastructure, Transport and Tourism.  

If a NOx figure cannot be provided for a vehicle then a flat charge will apply.  Further information can be found in Calculating the Nitrogen Oxide Charge.

Next: Nox Charge