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WLTP vs NEDC Comparison

How the transition from NEDC to WLTP test standards affects your VRT calculation, including CO2 differences, band shifts, and which standard applies to your vehicle.

Key Takeaways

  • WLTP produces 10 — 30% higher CO2 figures than NEDC for the same vehicle
  • Higher CO2 can push vehicles into higher VRT bands, increasing registration tax
  • Vehicles registered before 1 September 2018 use NEDC; after use WLTP
  • You must use the official figure from the Certificate of Conformity — you cannot choose
  • The band shift can add €500 — €3,000+ to VRT for vehicles near band boundaries

What Is NEDC?

The New European Driving Cycle (NEDC) was the standard method for measuring vehicle emissions and fuel economy in Europe from 1970 until it was phased out in 2017. The test was conducted on a rolling road dynamometer in a controlled laboratory environment, following a predetermined driving pattern that included urban and extra-urban phases.

The NEDC test was widely criticised for being unrealistic. The driving pattern was smooth and predictable, with gentle acceleration, no real-world variables like wind resistance, road gradient, or air conditioning usage, and the test speeds were lower than typical motorway driving. As a result, NEDC figures consistently underestimated real-world fuel consumption and CO2 emissions.

For VRT purposes, the NEDC CO2 figure was used to determine the VRT band for vehicles registered before the WLTP transition. These figures are still relevant for older imported vehicles, and Revenue continues to accept NEDC figures for vehicles that were originally type-approved under that standard.

The NEDC test cycle lasted approximately 1,180 seconds (about 20 minutes) and covered a distance of approximately 11 kilometres. The maximum speed was 120 km/h, and the average speed was only 34 km/h. The test included a cold start, four repeated urban cycles, and one extra-urban cycle. The controlled conditions and gentle driving pattern meant that vehicles consistently achieved better results than they would in real-world driving.

What Is WLTP?

The Worldwide Harmonised Light Vehicles Test Procedure (WLTP) replaced NEDC as the standard emissions test in Europe from September 2017 (initially for new type approvals) and September 2018 (for all new registrations). WLTP was developed by the United Nations Economic Commission for Europe (UNECE) to provide a more realistic and globally harmonised test standard.

WLTP addresses many of the criticisms of NEDC. The test cycle is longer (1,800 seconds versus 1,180 seconds), covers more distance (approximately 23 kilometres versus 11 kilometres), includes higher speeds (up to 131 km/h versus 120 km/h), and incorporates more dynamic driving with harder acceleration and deceleration. The test also accounts for vehicle weight, tyre type, and aerodynamic properties more accurately.

The result is that WLTP figures are consistently higher than NEDC figures for the same vehicle. The increase varies by vehicle type and powertrain, but the typical range is 10 — 30% higher CO2 under WLTP. Some vehicles, particularly those with stop-start systems and efficient aerodynamics, may show smaller increases, while performance vehicles and SUVs may show larger increases.

For VRT purposes, the WLTP CO2 figure determines the VRT band for vehicles registered from September 2018 onwards. Revenue uses the WLTP figure from the Certificate of Conformity, and importers cannot choose the NEDC figure even if both are available.

CO2 Differences: NEDC vs WLTP

To understand the real-world impact on VRT, here are typical CO2 differences for popular imported vehicle models:

Vehicle Model NEDC CO2 WLTP CO2 Increase
Volkswagen Golf 1.6 TDI 99 g/km 115 g/km +16%
BMW 320d 102 g/km 118 g/km +16%
Mercedes C220d 105 g/km 123 g/km +17%
Audi A4 2.0 TDI 108 g/km 127 g/km +18%
Toyota RAV4 Hybrid 100 g/km 118 g/km +18%
Hyundai Tucson 1.6 CRDi 115 g/km 139 g/km +21%
Volvo XC60 D4 120 g/km 148 g/km +23%
BMW X5 xDrive30d 140 g/km 178 g/km +27%

The pattern is clear: WLTP figures are consistently higher than NEDC, with larger vehicles and SUVs showing bigger increases. This is because the WLTP test more accurately captures the aerodynamic drag, weight, and tyre resistance of larger vehicles, which the NEDC test underestimated.

The VRT impact of these increases depends on where the vehicle sits relative to the band boundaries. A vehicle that shifts from Band C (111 — 140 g/km, 15.6%) to Band D (141 — 155 g/km, 20.1%) under WLTP faces a 4.5 percentage point increase in the VRT rate. On a €30,000 OMSP, that translates to an additional €1,350 in base VRT.

VRT Band Shifts: How WLTP Changes Your Tax

The most significant impact of the NEDC to WLTP transition is band shifting. When a vehicle’s CO2 figure increases under WLTP, it can move from one VRT band to a higher one, resulting in a higher tax rate. Here are the most common band shifts observed in practice:

Common NEDC → WLTP Shift Band Change Rate Increase VRT Impact (€30k OMSP)
B → C (61-110 to 111-140) 10.1% → 15.6% +5.5% +€1,650
C → D (111-140 to 141-155) 15.6% → 20.1% +4.5% +€1,350
D → E (141-155 to 156-170) 20.1% → 24.6% +4.5% +€1,350
E → F (156-170 to 171-190) 24.6% → 29.1% +4.5% +€1,350
F → G (171-190 to 191-225) 29.1% → 34.6% +5.5% +€1,650

The financial impact of a band shift is significant. A vehicle that crosses even one band boundary under WLTP faces an additional €1,350 — €1,650 in base VRT on a €30,000 OMSP. On higher-value vehicles, the impact is proportionally larger. For a €50,000 OMSP vehicle, a single band shift adds €2,250 — €2,750 in VRT.

The vehicles most affected by band shifting are those that sit close to band boundaries under NEDC. A car with 108 g/km NEDC CO2 (comfortably in Band B at 61 — 110) might shift to 127 g/km under WLTP, pushing it into Band C. The 28 g/km increase is enough to cross the boundary, and the tax consequence is real.

Which Standard Applies to Your Vehicle?

Revenue uses the test standard that corresponds to the vehicle’s date of first registration. The key date is 1 September 2018:

Registration Date Test Standard Notes
Before 1 September 2017 NEDC NEDC-only type approval. Use NEDC figures.
1 September 2017 — 31 August 2018 NEDC or WLTP Transition period. Check Certificate of Conformity for which figure is provided.
From 1 September 2018 WLTP All new registrations must use WLTP. Revenue uses WLTP figure.

During the transition period (September 2017 — August 2018), some vehicles were type-approved under both NEDC and WLTP. In these cases, Revenue uses the WLTP figure if it is available on the Certificate of Conformity. If only the NEDC figure is provided, that figure is used.

You cannot choose the more favourable standard. Revenue will use the official figure from the Certificate of Conformity that corresponds to the vehicle’s type approval and registration date. Attempting to use the wrong figure can result in a reassessment, penalties, and interest charges.

Worked Example: Band Shift Impact

Let us compare the VRT for a Volkswagen Golf 2.0 TDI under both test standards to see the real financial impact of the NEDC to WLTP transition.

Under NEDC (2017 model, registered August 2018)

OMSP: €22,000 | NEDC CO2: 105 g/km (Band B, 10.1%) | Age: 4 years

Step 1: Base VRT = €22,000 × 10.1% = €2,222

Step 2: Age reduction (4 years) = 30% = €667

Step 3: Adjusted VRT = €2,222 ‒ €667 = €1,555

Under WLTP (2019 model, registered September 2018)

OMSP: €23,000 | WLTP CO2: 126 g/km (Band C, 15.6%) | Age: 4 years

Step 1: Base VRT = €23,000 × 15.6% = €3,588

Step 2: Age reduction (4 years) = 30% = €1,076

Step 3: Adjusted VRT = €3,588 ‒ €1,076 = €2,512

WLTP increase: €957 — The WLTP-transitioned vehicle pays nearly €1,000 more in VRT despite being only marginally newer and having a similar engine. The band shift from B to C is the primary driver, combined with a slightly higher OMSP.

Implications for Importers

The NEDC to WLTP transition has significant implications for Irish car importers:

Older imports may be cheaper: Vehicles registered before September 2018 with NEDC figures can have lower VRT than newer identical models tested under WLTP. This creates a financial incentive to import slightly older vehicles, though this must be balanced against the age depreciation factor.

Comparing like-for-like: When comparing vehicles from different model years, make sure you are comparing the same test standard. A 2017 model with 105 g/km NEDC is not directly comparable to a 2019 model with 126 g/km WLTP, even though they may have the same engine.

Certificate of Conformity is critical: Always check the Certificate of Conformity for the official CO2 figure and the test standard used. This is the figure Revenue will use, and it determines your VRT band and tax liability.

Some manufacturers have redesigned engines: In response to WLTP, some manufacturers have updated their engines to achieve lower CO2 under the new test. This means some post-WLTP vehicles may have similar or even lower CO2 than their pre-WLTP predecessors, despite the more demanding test. These engines are worth seeking out for VRT purposes.

Key Takeaways

1. WLTP produces higher CO2 figures — Typically 10 — 30% higher than NEDC for the same vehicle. This is because WLTP is a more realistic and demanding test.

2. Band shifts increase VRT — Vehicles near band boundaries under NEDC can shift to higher bands under WLTP, adding €500 — €3,000+ to the VRT bill.

3. The applicable standard depends on registration date — Before September 2018: NEDC. After September 2018: WLTP. You cannot choose.

4. Check the Certificate of Conformity — This document contains the official CO2 figure and test standard that Revenue will use for your VRT calculation.

5. Pre-WLTP imports can save money — Older vehicles with NEDC figures may have lower VRT than newer models tested under WLTP, even if the engines are identical.

Frequently Asked Questions

What is the difference between WLTP and NEDC for VRT?

NEDC was the older test standard that produced lower CO2 figures. WLTP is the newer, more realistic standard that produces higher CO2 figures (typically 10 — 30% higher). Revenue uses the standard that corresponds to the vehicle’s date of first registration.

Which test standard does my car use for VRT?

Vehicles first registered before 1 September 2018 generally use NEDC figures. Vehicles registered from 1 September 2018 onwards use WLTP figures. Check your Certificate of Conformity for the official figure and test standard.

Does WLTP increase VRT costs?

Yes, typically. WLTP produces higher CO2 figures, which can push vehicles into higher VRT bands. The increase varies by vehicle but is commonly 10 — 30% higher CO2, which can add €500 — €3,000+ to the VRT bill depending on the vehicle’s OMSP and band shift.

Can I use the NEDC figure if my car was tested under both standards?

No. If your vehicle has a WLTP figure on its Certificate of Conformity, Revenue will use that figure. You cannot choose the NEDC figure even if it is lower. During the transition period (September 2017 — August 2018), check which figure appears on your CoC.

Related Calculators and Guides

🚗 VRT Calculator Calculate VRT for any vehicle imported to Ireland 📊 NEDC vs WLTP Guide Detailed guide to emissions test standards 📊 VRT Emissions Calculator Calculate VRT based on CO2 emissions 📖 How VRT Is Calculated Step-by-step VRT calculation guide

About the Author

Sarah Murphy is an automotive import specialist with over 10 years of experience helping Irish car importers navigate VRT, customs, and vehicle registration. She has assisted thousands of importers with accurate VRT estimates and has been featured in Irish motoring publications.

Questions? Contact the VRT Calculator team for expert advice on vehicle registration tax in Ireland.

Why WLTP Was Introduced

The move to WLTP was driven by growing evidence that real-world vehicle emissions were significantly higher than NEDC laboratory results. Studies by the European Environment Agency found that the gap between NEDC test results and real-world driving emissions had widened to 40 — 50% by the mid-2010s. This means vehicles that officially emitted 120 g/km CO2 were actually emitting 170 — 180 g/km on the road.

The NEDC test was designed in the 1970s and had not been significantly updated to reflect modern driving conditions. The test cycle was too gentle, the laboratory conditions were too controlled, and the test did not account for auxiliary loads like air conditioning, heated seats, or infotainment systems. Manufacturers had also become adept at optimising their engines specifically for the NEDC test cycle, a practice known as “cycle beating,” which further widened the gap between test results and real-world performance.

WLTP was designed to close this gap. The test includes a wider range of driving conditions, more aggressive acceleration and deceleration, higher speeds, and accounts for vehicle equipment and aerodynamic variations. The result is a more honest and comparable set of emissions figures across all vehicles. While this means higher CO2 numbers and potentially higher VRT, it also means that the figures more accurately reflect the environmental impact of the vehicle.

For Irish importers, the practical impact is that WLTP makes vehicles appear more polluting on paper, which translates to higher VRT bands. However, this is a reflection of the test being more realistic rather than the vehicles becoming less efficient. A 2019 Golf 1.6 TDI is not inherently more polluting than a 2017 model — it is simply tested under a more demanding and honest standard.

Double-Switch Impact: NEDC to WLTP and NOx Levy

The NEDC to WLTP transition coincided with the introduction of the NOx levy for diesel vehicles in Ireland. Vehicles registered before 2021 were not subject to the NOx levy, while newer vehicles are. This creates a double cost increase for importing newer diesel vehicles: the higher CO2 under WLTP pushes the vehicle into a higher VRT band, and the NOx levy adds an additional charge on top.

Consider the example of a Volkswagen Passat 2.0 TDI. A 2017 model tested under NEDC with 108 g/km CO2 falls into Band B at 10.1% and pays no NOx levy. A 2022 model tested under WLTP with 131 g/km CO2 falls into Band C at 15.6% and pays a NOx levy of approximately €900. The combined impact is substantial:

2017 Passat (NEDC): Base VRT = €22,000 × 10.1% = €2,222. After 50% age reduction (6+ years): €1,111. NOx: €0. Total VRT: €1,111

2022 Passat (WLTP): Base VRT = €28,000 × 15.6% = €4,368. After 10% age reduction (2 years): €3,931. NOx: €900. Total VRT: €4,831

The newer vehicle costs €3,720 more to register, driven by the higher OMSP, the WLTP band shift, and the NOx levy. This demonstrates why understanding both the test standard and the NOx levy is essential for importers targeting diesel vehicles.

How to Check Your Vehicle’s Test Standard

To determine which test standard applies to your vehicle, follow these steps:

Step 1: Check the date of first registration. This is on the vehicle’s registration document (V5C for UK vehicles, or the equivalent EU registration certificate). If the date is before 1 September 2018, the vehicle is likely NEDC-tested. After that date, it is WLTP.

Step 2: Check the Certificate of Conformity (CoC). The CoC contains the official CO2 emissions figure and will state whether it is NEDC or WLTP. This is the definitive source for Revenue. If the CoC shows both figures, Revenue uses the WLTP figure if available.

Step 3: Use the Revenue OMSP tool. Revenue’s Online Service (ROS) includes an OMSP lookup tool that shows the CO2 figure and test standard they have on record for your vehicle. This can help you confirm which standard applies before you commit to a purchase.

Step 4: Check with the manufacturer. If you are unsure about the test standard for a specific vehicle, the manufacturer’s local dealer or importer can confirm the type approval details from the vehicle identification number (VIN).

Getting the test standard right is critical because it determines your VRT band and therefore your tax liability. Using the wrong figure, even accidentally, can result in Revenue issuing a reassessment with interest and potential penalties.

Summary: WLTP vs NEDC at a Glance

Feature NEDC WLTP
Test Duration 1,180 seconds (~20 min) 1,800 seconds (30 min)
Distance Covered ~11 km ~23 km
Maximum Speed 120 km/h 131 km/h
Driving Patterns Smooth, predictable Dynamic, varied
CO2 Results Lower (underestimates) Higher (more realistic)
Real-World Gap 40 — 50% underestimate 10 — 20% underestimate
Applies To (Ireland) Before Sept 2018 From Sept 2018
VRT Impact Lower bands, lower tax Higher bands, higher tax

The transition from NEDC to WLTP was necessary to provide accurate and comparable emissions data. While it has increased VRT costs for many vehicles, it has also made the tax system more honest. Importers who understand the differences between the two standards can make smarter purchasing decisions, targeting vehicles that offer the best value when both the test standard and VRT implications are considered.

Special Case: Dual-Tested Vehicles

During the transition period (September 2017 — August 2018), some manufacturers type-approved their vehicles under both NEDC and WLTP. For these dual-tested vehicles, the Certificate of Conformity may show both figures. In practice, Revenue uses the WLTP figure if it is available, because WLTP was the newer and more accurate standard at the time of type approval.

For importers, this means that a vehicle from the transition period may have both figures available, but the WLTP figure is what Revenue will use for the VRT calculation. If you are comparing a transition-period vehicle with an older NEDC-only vehicle, make sure you are comparing the correct figures for each.

Some dealers and importers may advertise the NEDC figure for transition-period vehicles because it is lower and more attractive. Be aware that this is not the figure Revenue will use, and the actual VRT may be higher than advertised if based on the NEDC number. Always verify the CO2 figure and test standard on the official Certificate of Conformity before committing to a purchase.

For vehicles registered from September 2018 onwards, only WLTP figures are available, so there is no ambiguity. The WLTP figure on the CoC is the one Revenue uses, and it is the only figure that matters for your VRT calculation.

WLTP Impact by Vehicle Segment

The CO2 increase under WLTP varies significantly by vehicle segment. Here is how different vehicle types are typically affected:

Vehicle Segment Typical NEDC to WLTP Increase Most Common Band Shift
City Car / Supermini +10 — 15% Usually stays in same band
Compact Hatchback +12 — 18% B → C (common near boundary)
Executive Saloon +15 — 22% C → D (frequent shift)
Mid-Size SUV +18 — 25% D → E or E → F
Large SUV / 4x4 +22 — 30% E → F or F → G
Performance Car +20 — 28% G → H (frequent shift)

City cars and superminis are least affected because they have small engines, light weight, and good aerodynamics that translate well to both test cycles. The CO2 increase is modest, and band shifts are uncommon. This makes small petrol imports relatively immune to the WLTP impact.

Executive saloons and mid-size SUVs are most affected because their larger size, greater weight, and less aerodynamic profiles are penalised more heavily by the WLTP test. These are also the most popular imported vehicle segments, which means the WLTP impact is felt by the largest number of Irish importers.

Performance cars face the steepest increases because their high-power engines, wide tyres, and aggressive aerodynamics produce significantly higher CO2 under the more realistic WLTP test. A performance car that appeared to be in Band F under NEDC may shift to Band H under WLTP, resulting in a VRT rate increase from 29.1% to 40.6% — an increase of 11.5 percentage points. On a €60,000 OMSP, that translates to an additional €6,900 in base VRT.

Practical Tips for Importers

Based on the WLTP vs NEDC analysis, here are practical tips for Irish importers:

1. Target vehicles just below band boundaries: If you are importing a vehicle tested under WLTP, look for models whose CO2 figure sits just below a band boundary. For example, a vehicle at 139 g/km (Band C) is significantly cheaper to register than one at 141 g/km (Band D), even though the difference is only 2 g/km.

2. Consider pre-WLTP imports for diesel: For diesel vehicles, importing a 2017 — 2018 model with NEDC figures can save both on the CO2 band and on the NOx levy (which only applies from 2021). The age depreciation factor also helps older vehicles.

3. Use the VRT calculator with both standards: When comparing vehicles, run the VRT calculation using both NEDC and WLTP figures to see the full range of possible outcomes. This helps you understand the worst-case scenario if the WLTP figure pushes the vehicle into a higher band.

4. Check the CoC before purchase: Never commit to a vehicle without first checking the Certificate of Conformity for the CO2 figure and test standard. A vehicle that appears cheap may have a higher VRT than expected if the WLTP figure is significantly higher than advertised.

5. Factor in the total cost: Remember that VRT is just one component of the total import cost. A vehicle with higher VRT but lower purchase price may still be cheaper overall than a vehicle with lower VRT but higher purchase price.

WLTP and Electric Vehicles

The WLTP transition had an interesting side effect on electric vehicles. Under NEDC, electric vehicles achieved extremely low CO2 figures that were already at or near zero, so the WLTP increase had minimal impact on their VRT band. A Nissan Leaf with 0 g/km under NEDC still has 0 g/km under WLTP. The VRT advantage of EVs is therefore unaffected by the test standard change.

However, plug-in hybrids (PHEVs) are more affected. Under NEDC, many PHEVs achieved CO2 figures of 30 — 40 g/km, placing them comfortably in Band A. Under WLTP, the same vehicles can register 45 — 65 g/km, which may push them from Band A (0%) into Band B (10.1%). On a €35,000 OMSP, this band shift adds €3,535 in base VRT.

The PHEV WLTP impact is particularly relevant for Irish importers because PHEVs were marketed heavily as VRT-efficient alternatives. A PHEV that appeared to be a zero-VRT option under NEDC may actually carry a meaningful VRT bill under WLTP. Importers considering PHEVs should verify the WLTP CO2 figure on the Certificate of Conformity to avoid surprises.

For buyers choosing between a PHEV and a BEV (battery electric vehicle), the WLTP transition reinforces the BEV advantage. BEVs remain at 0% VRT regardless of test standard, while PHEVs may face 10.1% or higher if their WLTP CO2 exceeds 60 g/km. This is one reason why the BEV market has grown faster than the PHEV market in Ireland since the WLTP transition.

WLTP and Motor Tax

While this guide focuses on VRT, it is worth noting that the WLTP transition also affects annual motor tax in Ireland. Motor tax is calculated based on CO2 emissions bands, and the same test standard applies. A vehicle with higher CO2 under WLTP will pay more in annual motor tax than the same vehicle tested under NEDC.

The motor tax implications mirror the VRT implications: vehicles that shift to higher CO2 bands under WLTP face higher annual motor tax bills. For diesel vehicles, this compounds the VRT impact because the motor tax bands for diesel are generally higher than for petrol at the same CO2 level.

When calculating the total cost of ownership, importers should factor in both the one-time VRT impact and the ongoing motor tax impact of the WLTP transition. A vehicle that shifts from Band B to Band C under WLTP will pay approximately €200 more per year in motor tax, which over 5 years adds €1,000 to the total cost.

This is another reason to carefully check the WLTP CO2 figure before committing to an import. The combined VRT and motor tax impact of a band shift can be substantial, and it affects both the upfront cost and the ongoing running costs of the vehicle.

Manufacturer Responses to WLTP

Many manufacturers have responded to the WLTP challenge by redesigning engines and powertrains to achieve lower CO2 under the new test. This has led to some notable developments:

Mild Hybrid technology: Several manufacturers (Audi, Mercedes, Suzuki) have introduced 48V mild hybrid systems that use a small electric motor to assist the combustion engine. These systems reduce CO2 under WLTP by enabling stop-start at higher speeds, coasting with the engine off, and electric torque fill during acceleration.

Updated diesel engines: Newer diesel engines with advanced injection systems, higher-pressure fuel rails, and improved aftertreatment can achieve lower CO2 under WLTP than their predecessors. A 2022 diesel engine may have similar or lower WLTP CO2 than a 2017 engine tested under NEDC, despite the more demanding test.

Transition to PHEV and BEV: The WLTP challenge has accelerated the shift towards plug-in hybrids and fully electric vehicles, which are less affected by CO2 test standards. Manufacturers are investing heavily in electrification partly because it sidesteps the WLTP CO2 challenge entirely.

Aerodynamic improvements: Active grille shutters, underbody panels, and optimised wheel designs have helped reduce the aerodynamic penalty that larger vehicles face under WLTP. These improvements benefit real-world fuel economy as well as test results.

The Future: RDE and Real-World Emissions

While WLTP is a significant improvement over NEDC, it is still a laboratory test. To further close the gap between test results and real-world emissions, the Real Driving Emissions (RDE) test was introduced alongside WLTP. RDE measures emissions while the vehicle is driven on actual roads, including a range of driving conditions, temperatures, and altitudes.

RDE is not yet used for VRT calculations in Ireland — Revenue currently uses the WLTP laboratory figure. However, RDE data is included on the Certificate of Conformity and may influence future policy decisions. If Ireland moves towards RDE-based VRT calculations, the tax implications could change significantly.

For now, importers should focus on the WLTP figure as the basis for their VRT calculations. The RDE test serves as a validation check on the WLTP result, ensuring that vehicles perform similarly on the road as they do in the laboratory. Vehicles that fail RDE limits may face manufacturer recalls or type approval issues, which could affect their value and desirability.

The trend towards more realistic emissions testing is likely to continue, and future test standards may further reduce the gap between laboratory and real-world results. For Irish importers, the key message is to always use the official CO2 figure from the Certificate of Conformity for VRT calculations, and to understand that this figure reflects the most accurate and up-to-date test standard available.

Worked Example: SUV Under Both Standards

SUVs are the vehicle segment most affected by the WLTP transition. Let us compare a Volvo XC60 D4 under both standards to see the full impact.

Under NEDC (2017 model)

OMSP: €32,000 | NEDC CO2: 120 g/km (Band C, 15.6%) | NOx: N/A (pre-2021) | Age: 5 years

Step 1: Base VRT = €32,000 × 15.6% = €4,992

Step 2: Age reduction (5 years) = 40% = €1,997

Step 3: Adjusted VRT = €4,992 ‒ €1,997 = €2,995

Step 4: NOx levy = €0 (pre-2021 registration)

Total VRT: €2,995

Under WLTP (2022 model)

OMSP: €38,000 | WLTP CO2: 148 g/km (Band D, 20.1%) | NOx: 38 mg/km | Age: 4 years

Step 1: Base VRT = €38,000 × 20.1% = €7,638

Step 2: Age reduction (4 years) = 30% = €2,291

Step 3: Adjusted VRT = €7,638 ‒ €2,291 = €5,347

Step 4: NOx levy (38 mg/km) = approximately €750

Total VRT: €5,347 + €750 = €6,097

WLTP increase: €3,102 — The WLTP-tested, post-NOx-levy vehicle costs more than double to register. Three factors contribute: the band shift from C to D (adding €1,748 in rate difference on €38,000), the higher OMSP, and the NOx levy. This example shows how the WLTP transition and NOx levy combine to create a significantly higher registration cost for newer diesel SUVs.

Common Mistakes to Avoid

When dealing with the NEDC to WLTP transition, importers should avoid these common errors:

Mistake 1: Assuming NEDC figures apply to all vehicles. Many importers assume that because they are importing a used vehicle, NEDC figures apply. In reality, any vehicle registered from September 2018 onwards uses WLTP figures regardless of whether it is new or used.

Mistake 2: Comparing NEDC and WLTP figures directly. A 2017 model with 105 g/km NEDC is not comparable to a 2019 model with 126 g/km WLTP. The difference is in the test, not necessarily the vehicle. Always check which standard applies before comparing vehicles.

Mistake 3: Relying on advertised CO2 figures. Online listings and dealer advertisements may show the more favourable NEDC figure for transition-period vehicles. Always verify the official figure on the Certificate of Conformity, which is the document Revenue uses.

Mistake 4: Forgetting the NOx levy for newer diesels. Vehicles registered from 2021 onwards attract the NOx levy in addition to the CO2-based VRT. This double impact is often underestimated by importers focused only on the CO2 band.

Mistake 5: Not accounting for the age reduction difference. A pre-WLTP vehicle registered in 2017 benefits from a higher age reduction (potentially 50% at 6+ years) than a post-WLTP vehicle registered in 2022 (only 10% at 2 years). This affects the final VRT calculation significantly.

Revenue Guidance on WLTP

Revenue has published guidance on how the WLTP transition affects VRT calculations. Key points from their guidance include:

Official figures only: Revenue uses the CO2 figure from the Certificate of Conformity. They do not accept alternative figures, estimates, or manufacturer declarations. The CoC is the only authoritative source.

No choice of standard: You cannot choose to use the NEDC figure if a WLTP figure is available. Revenue will use the WLTP figure for any vehicle type-approved under that standard, regardless of whether the NEDC figure is also listed.

Transition period: For vehicles registered between September 2017 and August 2018, Revenue uses the WLTP figure if available on the CoC. If only NEDC is provided, they use that figure.

OMSP unchanged: The WLTP transition does not affect how Revenue calculates OMSP. OMSP is based on the Irish market value of the vehicle, independent of the test standard used for CO2.

Importers should familiarise themselves with Revenue’s guidance to avoid costly mistakes. Revenue’s VRT guidance is available on revenue.ie, and the OMSP tool on ROS provides indicative values for common imported models.

Comparison: Pre-WLTP vs Post-WLTP Imports

To put the numbers in perspective, here is a side-by-side comparison of importing the same model under pre-WLTP and post-WLTP conditions:

Factor Pre-WLTP (2017) Post-WLTP (2022)
Test Standard NEDC WLTP
CO2 (g/km) 105 126
VRT Band B (10.1%) C (15.6%)
OMSP €22,000 €28,000
Age 6 years (50% reduction) 2 years (10% reduction)
Base VRT €2,222 €4,368
Age-Adjusted VRT €1,111 €3,931
NOx Levy €0 €900
Total VRT €1,111 €4,831

The newer vehicle costs 4.3 times more to register, driven by the higher OMSP, the WLTP band shift, the lower age reduction, and the NOx levy. While the newer vehicle is newer, better equipped, and more efficient in real-world driving, the registration cost difference is substantial and must be factored into any purchasing decision.

This comparison also illustrates why pre-WLTP diesel imports from 2016 — 2017 remain popular in Ireland. The combination of NEDC-tested low CO2, no NOx levy, and maximum age depreciation makes these vehicles exceptionally VRT-efficient. The trade-off is that they are older vehicles with potentially higher mileage and more wear, but for budget-conscious importers, the VRT savings can be compelling.

WLTP and Import Strategy

Understanding the WLTP transition should inform your overall import strategy. Here are three approaches based on different buyer profiles:

Budget-focused importers: Target pre-WLTP diesel vehicles (2015 — 2017) from the UK or EU. These vehicles benefit from NEDC-tested low CO2, no NOx levy, and maximum age depreciation. The VRT can be as low as €500 — €1,500 for vehicles in this bracket. The trade-off is higher mileage and older technology.

Balance-focused importers: Target early WLTP vehicles (2019 — 2020) that have been redesigned for the new test. Many manufacturers updated their engines in 2019 to achieve better WLTP results, so a 2019 model may have lower WLTP CO2 than a 2018 model. These vehicles offer modern safety and technology with moderate VRT costs.

Technology-focused importers: Consider PHEVs or BEVs that sidestep the WLTP CO2 challenge entirely. PHEVs in Band A (under 60 g/km WLTP) pay 0% VRT, and BEVs pay zero regardless. The higher purchase price is offset by the VRT savings and lower running costs.

Glossary of Terms

NEDC: New European Driving Cycle — the older emissions test standard used in Europe until 2017.

WLTP: Worldwide Harmonised Light Vehicles Test Procedure — the newer, more realistic emissions test standard that replaced NEDC.

CO2: Carbon dioxide — the primary greenhouse gas measured in vehicle emissions testing. Used to determine VRT band placement.

NOx: Nitrogen oxides — pollutants that contribute to air quality problems. The NOx levy applies to diesel vehicles based on their NOx emissions.

CoC: Certificate of Conformity — the official document that states a vehicle’s type approval details, including CO2 emissions and test standard.

OMSP: Open Market Selling Price — the realistic value of the vehicle in the Irish market, used as the base for VRT calculation.

RDE: Real Driving Emissions — a road-based emissions test that validates laboratory results under real-world conditions.

VRT: Vehicle Registration Tax — the one-time tax paid when registering a vehicle in Ireland for the first time.

Band Shift: When a vehicle moves from one VRT band to another due to the difference between NEDC and WLTP CO2 figures.

Age Depreciation: The reduction in base VRT applied to vehicles over 12 months old, ranging from 10% to 50%.

WLTP Impact on Specific Popular Imports

Here is a detailed breakdown of how the WLTP transition affects some of the most popular imported vehicles in Ireland:

Vehicle NEDC Band WLTP Band VRT Increase (€30k OMSP)
VW Golf 1.6 TDI B (10.1%) C (15.6%) +€1,650
BMW 320d B (10.1%) C (15.6%) +€1,650
Mercedes C220d B (10.1%) C (15.6%) +€1,650
Audi A4 2.0 TDI B (10.1%) C (15.6%) +€1,650
Hyundai Tucson CRDi C (15.6%) D (20.1%) +€1,350
Volvo XC60 D4 C (15.6%) D (20.1%) +€1,350
BMW X5 xDrive30d D (20.1%) F (29.1%) +€2,700
Range Rover Sport E (24.6%) G (34.6%) +€3,000

The data shows a clear pattern: compact and executive cars typically shift one band (adding €1,350 — €1,650 on a €30,000 OMSP), while larger SUVs can shift two or more bands (adding €2,700 — €3,000+). The more efficient compact cars are least affected, while the larger, heavier vehicles are most impacted.

For importers, this data reinforces the importance of checking the WLTP CO2 figure before purchase. A vehicle that appears to be in a low-cost band under NEDC may actually be in a significantly higher band under WLTP, with a correspondingly higher VRT bill.

Final Recommendations

Based on our comprehensive analysis of the WLTP vs NEDC transition and its impact on VRT in Ireland, here are our final recommendations for importers:

Always verify the test standard: Check the Certificate of Conformity for the CO2 figure and test standard before committing to any purchase. This is the single most important document for your VRT calculation.

Use the official VRT calculator: Our VRT Calculator uses the correct CO2 figures and test standards for your vehicle. Input the WLTP figure if the vehicle was registered after September 2018.

Consider the total cost: VRT is just one part of the total import cost. Factor in customs duty (UK imports), VAT, shipping, and the ongoing motor tax impact of the CO2 band.

Target vehicles strategically: If VRT efficiency is a priority, look for vehicles with WLTP CO2 just below band boundaries, or consider pre-WLTP imports for older, more VRT-efficient diesel vehicles.

Stay informed: The emissions testing landscape continues to evolve. Revenue periodically updates its VRT guidance, and the government may adjust tax incentives for electric and hybrid vehicles. Check our VRT Changes and Updates 2026 page for the latest information.

Resources and Further Reading

For more information on VRT, emissions testing, and vehicle importation, explore these resources:

Understanding the WLTP vs NEDC transition is just one part of the import puzzle. Use our calculators and guides to ensure you make an informed decision and pay the correct amount of VRT on your imported vehicle.

Summary Table: WLTP vs NEDC Cost Impact

The following table summarises the typical VRT cost impact of the WLTP transition across different vehicle scenarios:

Scenario Typical VRT Increase Primary Driver
Compact car, same band €0 — €500 Higher OMSP only
Compact car, one band shift €1,000 — €1,650 Band rate increase + OMSP
Executive car, one band shift €1,500 — €2,500 Band rate increase + higher OMSP
SUV, one band shift + NOx €2,000 — €3,500 Band shift + NOx levy + OMSP
Large SUV, two band shifts + NOx €3,000 — €5,000+ Multiple band shifts + NOx + OMSP

The impact scales with vehicle size and value. Compact cars in the same band see minimal increases, while large SUVs with multiple band shifts and NOx levy exposure face the highest costs. Importers should budget for the worst-case scenario and verify all figures before committing to a purchase.