You are browsing mobile.de or AutoScout24 for a car to bring to Portugal. The German price is clear; the real question is what the import tax adds. The one-off registration tax — ISV — can be €300 or €15,000 depending on engine size, CO₂ and the car's age. We built a free Chrome extension that shows ISV and the annual IUC right on the listing — one click, no copying numbers into a calculator.
An honest caveat first: any such figure is an estimate based on the official 2026 formula. The final amount is set by the Portuguese tax authority (AT) when the DAV declaration is filed. But for a buy/skip decision, a euro-accurate estimate is exactly what you need.
What ISV is and why you should know it before buying a car for Portugal
ISV (Imposto Sobre Veículos) is a one-off tax paid when a car is first registered in Portugal. People often call it "import duty", but strictly speaking there is no customs duty inside the EU — it is a registration tax. It has two components: engine displacement and CO₂ emissions. Used cars get an age reduction — up to 80% for cars older than 10 years. There is also the annual IUC road tax — worth checking upfront, as it can be substantial for powerful cars.
We break the formula down in our ISV calculator, where you can also compute everything manually. But manual means retyping displacement, CO₂, registration date and fuel from the listing. The extension does that for you.
Three ways to estimate the import tax
| Method | What it takes | Time |
|---|---|---|
| Official AT simulator | Portal das Finanças login, manual entry | ~10 min |
| Our ISV calculator | Retype the listing data (or paste a link) | ~2 min |
| Chrome extension | Open the listing, click the icon | ~2 seconds |
All three use the same official formula — our calculator and the extension are verified cent-for-cent against the AT simulator on typical cases.
What the extension does
- Reads engine size, CO₂, first registration, fuel and price from the open listing.
- Computes ISV (import) and IUC (annual) for Portugal — 2026 formula, with the age reduction, EV exemption and plug-in hybrid reduction.
- Gives a share link — the calculation opens on our site, ready to send to a chat or save.
- A "Buy with delivery" button — if you want us to handle the import end-to-end, from the seller to Portuguese plates.
Works on mobile.de and AutoScout24 (all European versions). It collects no personal data — it only reads the car specs in the tab you opened.
How to install: one click
The extension is live on the Chrome Web Store — install it in one click. Manual .zip install is still available on the extension page.
How it works: an example
Open a BMW M8 listed at €99,850 (4.4 L, 265 g CO₂, 2025). One click: ISV ≈ €30,808, IUC ≈ €983/year. Decision made in seconds, with zero numbers typed. For electric cars the extension shows the exemption immediately: ISV €0 — fully electric cars are exempt in Portugal.
If the listing lacks some data (new made-to-order cars often omit displacement), the extension highlights the missing field and asks you to fill it — instead of showing a bogus number.
What the extension does not do
- It does not replace the DAV declaration or the tax authority's assessment — AT always sets the final amount.
- It does not promise "you save €X" — importing is not always the better deal, and we say so openly in is importing a car worth it.
- It does not collect your data or track your browsing.
Next step: legalisation
Car chosen? Next come DAV, inspection, ISV and plates. The full step-by-step is in our car legalisation guide for Portugal. Prefer not to deal with it — we import turn-key.
FAQ
Is the estimate accurate?
It follows the official 2026 formula and is verified against the AT simulator. The final amount is set by the tax authority during legalisation. Cars without a listed CO₂ value get a clearly marked rough estimate.
Is it free?
Yes, and it stays free. We earn on the import service — if you choose to order it.
Which sites are supported?
mobile.de and AutoScout24 (.com/.de/.at/.it/.es/.fr/.nl/.be/.lu). More to come.
What about electric cars?
Fully electric cars are ISV-exempt — the extension shows €0 right away and doesn't ask for engine size.
Firefox version?
Not yet, planned. For now: Chrome and Chromium-based browsers (Edge, Brave, Opera can install Chrome extensions).