IUC explained: who pays, how much, and when (with a real car table)

Short answer: the IUC (Imposto Unico de Circulacao) is the yearly road tax you pay simply for owning a car registered in your name. On a budget used car in Portugal it almost always lands between 46 and 170 euros a year — that is 4 to 14 euros a month. It is not scary: it is small and, unlike an inspection or a breakdown, you know the exact figure before you buy. How much you pay comes down to two things: the date of first registration (before or after 1 July 2007) and, on newer cars, the CO2 emissions. See the table below for five real cars and the exact IUC on each.

The fast way to check yours: drop the engine size, CO2 and year into our IUC calculator and you get the figure in seconds. The rest of this article explains where that number comes from, so nothing surprises you.

What the IUC is

The IUC replaced the old "car stamp" in 2007. It is paid by whoever owns the car on 1 January of each year — the name on the vehicle registration document (DUA). It is not about use: you pay the same if the car sits in the garage all year. And it is not the ISV, the tax you pay once when a car first enters Portugal or gets a new plate. ISV is a one-off on entry; IUC is every year.

One thing that matters if you are buying: the IUC sticks to the car, not the person. Buy in May and you inherit the car with that year's tax already set — and if the previous owner left years unpaid, that problem arrives with the keys. More on that at the end.

The two regimes: before and after July 2007

Here is what trips everyone up. There are two sets of rules, and the line is the date of first registration:

• Before 1 July 2007 (Category A): the IUC looks only at engine size (plus a small add-on if it is diesel). CO2 does not count. The result is low figures, often 40 to 130 euros a year, even on a big diesel.
• From 1 July 2007 onward (Category B): the IUC adds engine size + CO2 emissions, and it climbs with the year (a coefficient rises for newer cars). A car that emits a lot of CO2 pays noticeably more.

In plain terms: two cars that look identical on paper can pay very different IUC just because of the month they were registered. A 2005 diesel might sit at 46 euros/year; a 2.0 diesel from 2012 with high CO2 jumps to around 279 euros/year. Same brand, similar shape, nearly six times the tax.

How much the IUC is — five real cars

Real figures, calculated with the 2026 table. Look at the first row (the pre-July-2007 car) against the others: same class of engine, much lower tax.

Read it like this: that 2003 Golf pays 46 euros for the whole year — under 4 euros a month — because it is Category A and only engine size counts. The 2014 Ford Focus 1.5 diesel pays 158 euros: engine size + CO2 + the small diesel add-on. And the older petrol Peugeot 207, with high CO2 (155 g/km), ends up paying more than the Focus. It is not the size of the car that decides — it is the mix of year, engine and CO2.

The pre-July-2007 trick

If you are stretching the budget, this is a real move: a car with first registration before 1 July 2007 pays IUC under the old rule (Category A), which ignores CO2. That is why the 2003 Golf 1.9 TDI sits at 46 euros while an equivalent 2012 diesel goes past 270. Similar engine; different registration year.

It is not a loophole or a scheme — it is the law. But watch the other side of the ledger: an older car saves on IUC and usually spends more on maintenance, parts and fuel. A low IUC does not pay for a timing belt or a clutch. See the full picture in how much it costs to run a cheap car in Portugal before you decide on tax alone.

When the IUC is due

The IUC falls due in the month of the car's first registration, every year. If the car was registered in March, every March you have to pay. No letter arrives to remind you — it is on you, and the deadline is the end of that month. You pay it all at once; there are no instalments.

How do you know the month? It is on the DUA and it also shows up the moment you enter the plate on the Portal das Financas. Practical rule for anyone who just bought: confirm the due month on the day of purchase, so you do not catch a fine over two days late.

How to check and pay on the Portal das Financas

The IUC is paid on the Portal das Financas, not at the dealer or the post office. The path:

• Log in to the Portal das Financas with your NIF and password (or Chave Movel Digital).
• Search "IUC" > "Emitir / Pagar". Enter the plate and the system shows the year's amount.
• Pay by Multibanco reference, MB WAY or direct debit. Keep the receipt.

If you want the figure before you have access to the car on the portal — say, on a car you are still thinking of buying — use our IUC calculator with the engine size, CO2 and year. It gives the same number the tax office will charge.

Unpaid IUC follows the car

This is the warning that matters when you buy used. The IUC is a debt tied to the vehicle. If the previous owner left years unpaid, those amounts (and the fines on top) do not vanish when the car changes hands — they can land on you and hold up the paperwork.

Before you close, ask the seller for proof the IUC is up to date (the receipt for the last year) and confirm nothing is outstanding. Two minutes, and you avoid inheriting someone else's bill. It is the same logic as never buying without seeing the registration document and the service history — the sticker price is not the real cost. On that, read how to buy a cheap used car without getting burned.

Work out your IUC in 20 seconds

Before you say yes to a car, put the engine size, CO2 and year into the IUC calculator and see the exact amount you will pay every year. Add it to insurance and maintenance — that is the cost of running the car, not just buying it. And if you are still deciding which car fits your budget, first check whether the asking price is fair with the fair-price checker.

Read also:how much it costs to run a cheap car in Portugal, what you get for 5,000, 8,000 and 10,000 euros, and how to buy a cheap used car without getting burned.