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Calculating Vehicle Registration Tax

  1. Overview
  2. Applying the tax
  3. Assessing the value
  4. Additional VRT
  5. VAT and Customs Duty
  6. Electric and hybrid vehicles
  7. Nitrogen Oxide emissions
  8. Calculating the NOx charge

Calculating the NOx charge

Basis of Charge

Nitrogen Oxide (NOx) emissions will be taxable beginning on 1 January 2020. The charge is applicable to all Category A vehicles excluding electrics but including hybrids. 

The NOx charge will be a component of vehicle registration tax as outlined below:

Carbon Dioxide charge + NOx Charge = Total VRT payable.

NOx is charged on the basis of milligrams per kilometre as recorded on the Certificate of Conformity. In the case of heavy duty vehicles this will be milligrams per kilowatt hour. 

Depending on documentation such as foreign registration certificates the figure may also be shown as grams per kilometre. This will not affect the tax due as Revenue will convert this to milligrams in the calculation at registration.

Amount due

The NOx charge will be calculated according to the following table:

Calculation of NOx charge
NOx emissions (NOx mg/km or mg/kWh)Amount payable per mg/km or mg/kWh

The first 0-60 mg/km or mg/kWh, as the case may be

€5

The next 20 mg/km or mg/kWh or part thereof, as the case may be, up to 80 mg/km or mg/kWh, as the case may be

€15

The remainder above 80 mg/km or mg/kWh, as the case may be

€25

If satisfactory evidence of NOx emissions cannot be provided the following maximum charges will apply:

  • Diesel vehicles: €4,850
  • or
  • All others: €600

Examples of the VRT calculation

  • Sample Vehicle 2016 4-door saloon, 1.8l

    Previous registration document:
    - CO2 (g/km) - 124
    - NOx (g/km) - 0.008
    - Open Market selling price (OMSP) - €27,871

    CO2 Component of VRT due - 124 g/km = 19% of OMSP = €5,295

    NOX Component of VRT due - 8 mg (0.008 g x 1,000) x €5 = €40

    Total VRT due (combined CO2 + NOx) = €5,335

  • Sample Vehicle 2006 5-door SUV, 3l

    Previous registration document:
    CO2 (g/km) - 213
    NOx (g/km) - 0.090
    OMSP - €2,542

    CO2 Component of VRT due - 213 g/km = 35% of OMSP = €889

    NOX Component of VRT due - 90 mg (0.090 g x 1,000)
    - first 60 g x €5 = €300
    - next 20 g x €15 = €300
    - next 10 g x €25 = €250
    - Total = €850

    Total VRT due (combined CO2 + NOx) = €1,739

  • Sample Vehicle 2015 5-door hatchback diesel, 1.9l

    Previous registration document:
    - CO2 (g/km) - 103
    - NOx (g/km) 
    - OMSP = €12,017

    CO2 Component of VRT due - 103 g/km = 17% of OMSP = €2,042

    NOX Component of VRT due - No satisfactory evidence of NOx presented. Charge default: €4,850

    Total VRT due (combined CO2 + NOx) = €6,892

  • Sample Vehicle 2010 2-door Sports Coupe, 5l petrol

    Previous registration document:
    - CO2 (g/km) 
    - NOx (g/km)  
    - OMSP - €30,847

    CO2 Component of VRT due - No satisfactory evidence of CO2 presented: 36% of OMSP = €11,105

    NOX Component of VRT due - No satisfactory evidence of NOx presented.  Charge default: €600

    Total VRT due (combined CO2 + NOx) = €11,705

Published: 19 October 2020 Print this page

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