ISV: how Portugal’s one-off vehicle tax is calculated

Updated 25 October 2026 · Legaliza na Hora

The two components

The two are added. A large engine weighs on the first component. High emissions weigh on the second. The measurement standard matters: WLTP figures are generally higher than NEDC figures and the applicable tables can differ. Using the CO2 value of a different version of the same model is one of the commonest and most expensive errors.

The reduction for age

A used car that was previously registered in another EU member state gets a reduction based on years of use, counted from the date of first registration to the date of the DAV, reaching up to 80% for a car more than ten years old. Since 2025 the reduction applies to the engine capacity component, the environmental component and the particulate component. Cars from outside the European Union get no age reduction at all, which is the main reason a British car is more expensive to bring in than the same car from Germany. See registering a UK car.

Electric and hybrid cars

The six figures we need to calculate your ISV

• The date of first registration.
• Engine capacity, in cm3.
• Fuel.
• CO2 emissions, in g/km.
• The measurement standard, NEDC or WLTP.
• For a diesel, the particulate emissions, if the COC shows them.

All of it is on the foreign registration document and the certificate of conformity. Photograph both and send them before you buy the car, and we will calculate the tax. You can also use the ISV simulator or the simulator for cars from outside the EU, both currently in Portuguese. A simulation is an estimate, not the Tax Authority’s assessment.

When ISV is paid

ISV is assessed on the DAV, the vehicle customs declaration, and has to be paid before the Portuguese registration number is issued. Under the general rules a private individual must present the DAV within 20 working days of the car entering Portugal, and the ISV payment deadline is 10 working days from the notification of the assessment. You pay the tax directly to the Tax Authority; it is never part of our fee. See who files the declaration.

ISV is not IUC, and it is not VAT

• ISV is paid once, at registration.
• IUC is the annual road tax, paid every year after the car has Portuguese plates.
• VAT applies only in certain cases. For VAT purposes an EU vehicle counts as used only when, at the time of sale, it is more than six months old and has travelled more than 6,000 km. A newer car can therefore carry Portuguese VAT as well. Cars from outside the EU have a different treatment: import VAT and customs duty on the value of the car.

The exemption for a transfer of residence

Someone moving their normal residence to Portugal and bringing their own car may be able to apply for an ISV exemption. The common rules require, among other conditions, at least six months of residence abroad and at least six months of ownership before the move, with the application made within 12 months of the transfer. After registration there is a 12 month restriction on selling, renting or lending the vehicle. Nationality does not decide eligibility: a non-Portuguese person moving to Portugal can be in exactly the same position. The decision belongs to the Tax Authority. Our service including the exemption application costs €596 including VAT. Read the transfer of residence guide.

Common mistakes

• Calculating the ISV after buying the car instead of before.
• Using the date of manufacture instead of the date of first registration.
• Comparing only the purchase price abroad with Portuguese prices, without adding the tax.
• Taking the CO2 value from another version of the model.
• Ignoring whether the figure is NEDC or WLTP.

What the whole bill looks like, tax included, is set out in what it costs to import and register a car.

Frequently asked questions

Official sources: Autoridade Tributária, ISV and VAT on vehicles. This page explains the structure of the tax. The assessment is made by the Tax Authority on the DAV.