You found a car you like on a UK site. A 2021 Volkswagen Golf, 1.5-litre petrol, 35,000 miles, looks clean. The price is €14,500. You start thinking about bringing it home to Ireland. Then someone mentions VRT and suddenly you're not sure what this car will actually cost you.
I've been there myself. You try to find a straight answer about how VRT is calculated, and you end up down a rabbit hole of Revenue PDFs, CO2 conversion formulas, and confusing band tables. When you book your VRT inspection, you will visit an NCTS (National Car Testing Service) centre, where they verify your vehicle's details before registration. It doesn't have to be this complicated.
In this guide, I'll walk you through exactly how the VRT formula works in Ireland, with real numbers you can follow along with. You'll learn about OMSP, the CO2 bands that determine your rate, the NOx levy that catches people out, and the reliefs that can bring your bill down. I've also included three detailed examples so you can see how it plays out with different types of cars.
Look, I'm not going to pretend this is exciting stuff. But knowing how VRT is calculated can save you thousands of euro. And if you're reading this because you're thinking about importing a car, you've already taken the first step toward making a smart decision. Let's get into the numbers.
The Problem with VRT: Why It Feels Like a Lottery
Here's what frustrates most people about VRT. You can't just look up a simple price list. The amount you pay depends on three main things: the car's value, its CO2 emissions, and its NOx emissions. And Revenue doesn't always see eye to eye with you on what the car is worth.
Let's say you buy a car in the UK for €10,000. You might think "great, VRT will be based on what I paid." Nope. Revenue has its own idea of what the car is worth in the Irish market, and they call that the OMSP. If their number is higher than your purchase price, you pay more.
Then there's the emissions side of things. A car with CO2 emissions just one gram over a band threshold could cost you hundreds more. I've seen someone import a diesel Audi A6 thinking the VRT would be around €3,000 and ended up with a bill over €6,000 because the NOx levy pushed it way up. You need to know the full picture before you commit.
Another thing I hear a lot is: "I'll just use the Revenue VRT calculator on ROS, that'll tell me exactly what I owe." And yes, that gives you an official estimate. But you still need to input the OMSP yourself, and you might not know what number to put in. Plus the calculator doesn't account for every relief or category nuance. So you end up guessing, which defeats the purpose.
That's why understanding the formula yourself is so valuable. Once you know how the pieces fit together, you can estimate VRT for any car you're considering, compare different vehicles, and walk into the registration process with confidence. You won't be one of those people who gets a shock at the VRT office.
The VRT Formula: Breaking It Down
For a standard passenger car (Category A), the formula is actually straightforward once you know the pieces:
Total VRT = CO2 Component + NOx Levy - Any Reliefs
The CO2 component is a percentage of the car's OMSP. The NOx levy is a separate charge based on nitrogen oxide emissions. And reliefs are deductions you might qualify for. That's it at a high level. Let's look at each piece in detail.
Step 1: Understanding OMSP Open Market Selling Price
OMSP is probably the most misunderstood part of VRT. It stands for Open Market Selling Price, and it's Revenue's estimate of what your car would sell for on the open market in Ireland, not what you paid for it abroad.
Revenue works out your car's OMSP by looking at similar cars for sale on Irish websites like DoneDeal and CarsIreland. They take into account the make, model, year, engine size, transmission, trim level, optional extras, mileage, and overall condition. Then they come up with a number.
If you imported a car with high mileage or in poor condition, the OMSP should reflect that. But here's where people get caught out. If the market in Ireland is strong for your model, Revenue's OMSP might be higher than what you realistically paid. And you can't just argue "but I only paid X for it" unless you have solid evidence that the Irish market value is lower.
A quick tip: before you buy, search DoneDeal for similar cars already in Ireland. Note down the prices of comparable models, especially ones with similar mileage and spec. This gives you a rough idea of what Revenue might use as the OMSP.
Here's something I've learned the hard way. Revenue doesn't just look at the average price of similar cars. They consider the specific trim level and optional extras. A 2020 Golf with the R-Line trim and a sunroof will have a higher OMSP than the same year Golf in a basic trim. So when you're comparing cars on DoneDeal, make sure you're comparing like with like. A base model with steel wheels and a high-mileage example with full service history are going to have very different OMSPs.
If Revenue sets the OMSP too high, you do have options. You can appeal the assessment, but you'll need proof. Screenshots of similar cars for sale at lower prices, a professional valuation, or evidence of damage or high mileage can all help. More on that in our guide to appealing VRT assessments.
Step 2: CO2 Emissions and VRT Bands
This is where the percentage-based charge kicks in. For a Category A passenger car, Revenue charges a percentage of the OMSP based on the car's CO2 emissions. Lower CO2 means a lower percentage, which means lower VRT.
The Current Band System
As of the latest Revenue guidance, here's how the bands break down for cars tested under WLTP (Worldwide Harmonised Light Vehicles Test Procedure):
- 0 to 120 g/km CO2 (WLTP): 8% of OMSP, minimum €160
- Over 120 g/km CO2 (WLTP): 13.3% of OMSP, minimum €266
Simple enough, right? Two bands. If your car is the cleaner kind, under 120 g/km, you get the lower 8% rate. If it's over 120 g/km, you pay 13.3%.
But there's a catch. Many cars, especially older ones, were tested under the older NEDC standard, which tends to give lower CO2 figures. Revenue converts NEDC figures to WLTP equivalents using a formula. So your car's official CO2 number might change when Revenue looks at it. I've seen NEDC figures jump up by 10 to 20 g/km after conversion. That can easily push a car from the 8% band into the 13.3% band.
How the CO2 Component Works
Let's say your car has a WLTP CO2 figure of 110 g/km. That's under 120, so you're in the 8% band. If Revenue sets the OMSP at €18,000, the CO2 component is:
8% of €18,000 = €1,440
If the car had come in at 125 g/km WLTP, it would fall into the higher band:
13.3% of €18,000 = €2,394
That's a difference of €954, just because the car emits 15 more grams of CO2 per kilometre. So you can see why checking the exact CO2 figure matters.
I'd recommend getting the CO2 figure from the Certificate of Conformity (CoC) rather than relying on an online database. The CoC is the official document from the manufacturer that lists all the technical specs. It'll have the exact WLTP or NEDC figure. Don't rely on what's listed on a UK dealer's website, because they sometimes list the old NEDC figure when the WLTP figure is higher.
Step 3: The NOx Levy Explained
The NOx levy is a separate charge that trips up a lot of importers. NOx stands for nitrogen oxides, and it's measured in milligrams per kilometre (mg/km). This is a cumulative, banded charge, meaning each portion of the NOx figure is taxed at a different rate.
NOx Levy Rates
| NOx Emissions (mg/km) | Charge per mg/km |
|---|---|
| 0 to 40 mg/km | €5 per mg |
| 41 to 80 mg/km (next 40 mg) | €15 per mg |
| Above 80 mg/km | €25 per mg |
There are caps to stop the levy from going crazy. For diesel cars, the cap is €4,850. For petrol and other vehicles, it's €600.
Working Through a NOx Example
Say your car has a NOx reading of 75 mg/km (common for a modern diesel):
- First 40 mg at €5 each = €200
- Next 35 mg (41 to 75) at €15 each = €525
Total NOx levy = €725
Compare that to a petrol car with NOx of 25 mg/km:
- First 25 mg at €5 each = €125
Total NOx levy = €125
That's a €600 difference. It's why diesel imports often look cheaper on paper but end up costing more once VRT is applied.
Step 4: VRT Reliefs That Can Reduce Your Bill
There are reliefs and exemptions available that can bring your VRT down. Here are the main ones worth knowing about:
VRT Relief for Electric Vehicles
Battery electric vehicles (BEVs) get notable VRT relief. As of 2026, the relief is up to €5,000 depending on the vehicle's value and the current scheme. Electric cars are also exempt from NOx charges because they produce zero tailpipe emissions.
Plug-in Hybrid Relief
Plug-in hybrid electric vehicles (PHEVs) may qualify for a reduced VRT rate if they meet certain CO2 and electric range requirements. The relief amount changes depending on the Budget, so it's worth checking the latest figures on Revenue.ie.
Disabled Drivers and Disabled Passengers Scheme
If you or someone you're caring for has a qualifying disability, you may be eligible for VRT remission or repayment. This is a specific scheme with its own application process, and you'll need medical certification.
Historic Vehicle Exemption
Cars over 30 years old may qualify for a reduced VRT rate. Revenue classes these as historic vehicles, and the minimum VRT charge typically applies, which is much lower than the standard calculation.
Three Detailed Examples: Different Cars, Different Bills
Let's put it all together with three real-world examples. Each car is different in terms of value, emissions, and fuel type, and I've used realistic 2025 figures.
Example 1: 2021 Toyota Corolla 1.8 Hybrid Petrol
Vehicle specs:
- OMSP: €16,000
- WLTP CO2: 103 g/km
- NOx: 12 mg/km
- Fuel type: Petrol hybrid
CO2 component: 103 g/km is under 120, so the rate is 8%. 8% of €16,000 = €1,280
NOx levy: 12 mg/km at €5 = €60. Cap for petrol is €600, so this is well within limits.
Total VRT: €1,280 + €60 = €1,340
This is a relatively low VRT bill for a popular family car. The hybrid's low CO2 keeps it in the lower band, and the petrol engine means minimal NOx. This is the kind of car that makes sense to import. If you were buying it for €14,000 in the UK and adding maybe €1,500 in shipping, customs, and VAT, the total landed cost would be roughly €16,800. That's competitive with Irish prices for the same car.
Example 2: 2019 BMW 520d M Sport Diesel
Vehicle specs:
- OMSP: €22,000
- WLTP CO2: 138 g/km
- NOx: 68 mg/km
- Fuel type: Diesel
CO2 component: 138 g/km is over 120, so 13.3%. 13.3% of €22,000 = €2,926
NOx levy: First 40 mg at €5 = €200. Next 28 mg at €15 = €420. Total = €620. Diesel cap is €4,850, so we're well under.
Total VRT: €2,926 + €620 = €3,546
This is where VRT starts to sting. The diesel engine pushes the CO2 over the 120 g/km threshold, and the NOx levy adds over €600. If you're looking at a premium diesel, expect a bill in this range. Add another €2,000 or so for customs and VAT on a €22,000 car, and you're looking at a total import cost of about €5,500 on top of the purchase price. That's a lot, but if the Irish market price for the same car is €30,000+, you might still come out ahead.
Example 3: 2022 Tesla Model 3 Electric
Vehicle specs:
- OMSP: €35,000
- WLTP CO2: 0 g/km
- NOx: 0 mg/km
- Fuel type: Electric
CO2 component: 0 g/km. But the minimum VRT for Category A is €160 (based on the 0-120 g/km band minimum). So the CO2 component is €160, not zero.
NOx levy: 0 mg/km = €0.
VRT relief: Electric vehicles qualify for VRT relief, which as of 2026 is typically up to €5,000 for battery EVs under a certain value. For this Model 3, the relief might reduce the VRT notably or eliminate it entirely.
Total VRT (before relief): €160
Total VRT (after relief): Likely €0
This shows why electric cars are such an attractive import option. Even without the relief, the VRT is minimal because of zero emissions. With the relief, it can be zero.
Common Mistakes People Make With VRT Calculations
I've seen the same mistakes come up again and again. Here's what to watch out for:
Mistake 1: Using the purchase price instead of OMSP. You might have bought the car for €8,000 in the UK, but Revenue might value it at €11,000 in Ireland. The VRT is based on Revenue's number, not yours.
Mistake 2: Forgetting about the NEDC to WLTP conversion. If your car only has an NEDC CO2 figure, Revenue will convert it. That new number could be notably higher. Always check what the WLTP-equivalent figure would be before estimating VRT.
Mistake 3: Ignoring the NOx levy on diesels. I've lost count of how many people budget based on the CO2 component alone. A diesel with high NOx can add thousands to your bill.
Mistake 4: Not factoring in the minimum VRT. Even very old, very cheap cars pay a minimum VRT. It's not zero. For the lower band, it's €160. For the upper band, it's €266. And you still pay the NOx levy on top.
Mistake 5: Assuming all electric cars pay zero VRT. While many electric cars end up with very low or zero VRT after reliefs, the relief amount can change. And if the car's value is very high, the relief might not cover the full charge.
How to Estimate Your VRT Before You Buy
The smart way to do this is to run the numbers before you travel or bid on a car. Here's a checklist:
- Find the car's CO2 figure (WLTP if possible, otherwise NEDC)
- Find the car's NOx figure (in mg/km, usually on the Certificate of Conformity)
- Search DoneDeal for similar cars in Ireland to estimate the OMSP
- Apply the CO2 band percentage to the estimated OMSP
- Calculate the NOx levy using the banded rates
- Add them together for your estimated VRT
- Check if any reliefs apply
- Use our VRT calculator to double-check your numbers
This won't be exact because Revenue has the final say on OMSP, but it will get you within a reasonable range. If your estimate is close to the official assessment when you register, you know you did it right.
Where to Find the Official Numbers
Revenue publishes the official VRT rates and bands on Revenue.ie. The VRT manual is the definitive source. It's a long document, but the key sections are:
- Part 2: Valuation (how OMSP is determined)
- Part 3: Charge and rates (the CO2 bands and percentages)
- Part 5: NOx levy (the full calculation rules)
- Part 6: Reliefs and exemptions
You can also use Revenue's own VRT calculator on ROS (Revenue Online Service) for an official estimate, but you'll need to bring your own numbers. The calculator won't tell you the OMSP in advance, so you need to have a reasonable idea of the car's market value yourself.
Final Thoughts: Know Your Numbers Before You Commit
VRT doesn't have to be a mystery. The formula is a simple addition once you know three things: the OMSP, the CO2 figure, and the NOx figure. Everything else flows from those numbers.
The mistake I see most often is people committing to a car before they understand the total cost. They see a low purchase price in the UK and assume the VRT will be a few hundred euro. Then the Revenue assessment comes in and it's three grand, and suddenly the deal doesn't look so good.
Run the numbers first. Use a VRT calculator if you want a quick estimate. Know your CO2, know your NOx, and have a realistic idea of the Irish market value for the car. That way, when you walk into the VRT office, you know what to expect and you won't get an unwelcome surprise.
What About Other VRT Categories?
This guide focuses on Category A passenger cars, because that's what most people are importing. But there are other categories worth knowing about:
- Category B: Light commercial vehicles like vans. These have their own CO2-based rates, and recent budgets have introduced lower rates for low-emission vans.
- Category C: Heavy commercial vehicles, agricultural tractors, and buses. These are usually taxed at a flat rate rather than a percentage of value.
- Category D: Exempt vehicles including certain diplomatic vehicles and some historic vehicles. No VRT due.
- Category M: Motorcycles. Taxed based on engine capacity rather than emissions.
If you're importing something unusual, check the Revenue VRT manual to see which category applies. The formula can be very different from what I've described above.
Want an instant estimate? Use our VRT calculator and enter the OMSP, WLTP CO2, and NOx to get a result straight away.
Frequently Asked Questions
1. Can I dispute the OMSP Revenue gives me?
Yes, you can appeal Revenue's OMSP assessment, but you need evidence. The process is covered in our guide to appealing VRT assessments. You'll need to show comparable Irish market sales at lower prices.
2. Does VRT include VAT and customs duty?
No. VRT is a separate tax. If you're importing from Great Britain, you'll also pay 10% customs duty on the purchase price and 23% VAT (VRT is also chargeable on top). These all add up, so budget for the full picture.
3. What if my car has no NOx figure?
If the NOx figure is missing from your Certificate of Conformity, Revenue may use a default value. This usually works against you, so try to get the official NOx reading before you register.
4. How long does a VRT payment last?
Once you pay VRT, the car is registered in Ireland permanently. Once complete, your vehicle receives an IRN (Irish Registration Number) and can be driven legally on Irish roads. You don't pay VRT again unless you re-register the car after a real change.
5. Are the VRT rates likely to change?
Rates are reviewed in each year's Budget. The thresholds and percentages can shift, and relief amounts have changed in recent years. Always check the current rates on Revenue.ie before doing your calculation.
Sources: Revenue.ie (VRT calculating and applying tax pages, VRT manuals), Government Budget announcements on VRT rates and reliefs.