If you own a car in Portugal, IUC is the bill that comes back every single year. Unlike ISV — the one-off tax you pay when a vehicle first enters the Portuguese fleet — IUC (Imposto Único de Circulação) is the recurring road tax you owe for as long as the car is registered in your name. This guide explains exactly how the 2026 figures are built, works through real examples, and flags the billing reform coming in 2027.
If you're bringing a vehicle in from abroad, start with our step-by-step guide to importing a car to Portugal for the ISV side; this page is about what you pay every year afterwards.
IUC vs ISV: Don't Confuse the Two
The two vehicle taxes catch people out constantly:
- ISV (Imposto Sobre Veículos) is a one-off registration tax, paid once when the car is first registered — or first legalised — in Portugal.
- IUC (Imposto Único de Circulação) is the annual ownership tax, paid every year on the vehicle's registration anniversary.
You pay ISV once and IUC forever. This guide is about IUC.
How IUC Is Built for a Modern Car (Category A)
For a private passenger car first registered from July 2007 onward, IUC is assembled from building blocks rather than a single rate. The core formula is:
IUC = (cilindrada band + CO2 band) × year coefficient + CO2 levy (where applicable) + diesel component (where applicable)
The cilindrada (engine-size) component — 2026
| Engine size | IUC component |
|---|---|
| Up to 1,250 cm³ | €31.77 |
| Over 1,250 to 1,750 cm³ | €63.74 |
| Over 1,750 to 2,500 cm³ | €127.35 |
| Over 2,500 cm³ | €435.84 |
The CO2 component — 2026
| CO2 (WLTP / NEDC) | IUC component |
|---|---|
| Up to 140 g/km (WLTP) / up to 120 g/km (NEDC) | €65.15 |
| 140 to 205 (WLTP) / 120 to 180 (NEDC) | €97.63 |
| 205 to 260 (WLTP) / 180 to 250 (NEDC) | €212.04 |
| Over 260 (WLTP) / over 250 (NEDC) | €363.25 |
The year-of-first-registration coefficient
The sum of the two components above is multiplied by a coefficient tied to the year the car was first registered: 2007 = 1.00; 2008 = 1.05; 2009 = 1.10; 2010 and later = 1.15. So most cars on the road today carry the full 1.15 multiplier.
The extras: CO2 levy and the diesel component
- Additional CO2 levy — for cars first registered after 1 January 2017, an extra €31.77 applies in the 205–260 g/km WLTP band and €63.74 above 260 g/km WLTP.
- Diesel component (adicional de gasóleo) — diesel cars add, by engine size: €5.02 (≤1,250 cm³), €10.07 (1,250–1,750), €20.12 (1,750–2,500) and €68.85 (over 2,500 cm³).
Every figure here is drawn from the current Código do IUC. You can see them, dated and sourced, on our verified vehicle-tax dataset.
Worked Examples
A 2018 petrol hatchback — 1,600 cm³, 130 g/km (WLTP).
- Cilindrada band (1,250–1,750): €63.74
- CO2 band (up to 140): €65.15
- Subtotal: €128.89 × 1.15 (registered post-2010) = ≈ €148.22/year
- No CO2 levy (under 205 g/km), no diesel component.
A 2019 diesel SUV — 1,950 cm³, 150 g/km (WLTP).
- Cilindrada band (1,750–2,500): €127.35
- CO2 band (140–205): €97.63
- Subtotal: €224.98 × 1.15 = €258.73
- Diesel component (1,750–2,500): €20.12
- Total: ≈ €278.85/year
These are illustrative — always confirm your car's exact CO2 typing (WLTP vs the older NEDC cycle uses different bands) and registration year, because both move the number.
Electric and Low-Emission Vehicles
Because the CO2 component is what drives most of the bill, emissions are the single biggest lever on what you pay. Full-electric vehicles (BEVs) are also exempt from ISV entirely — they are not subject to the one-off registration tax — which makes a battery-electric import dramatically cheaper to bring in and cheaper to run year on year. If you're weighing petrol against diesel against electric, the recurring IUC gap compounds over the life of the car.
What's Changing in 2027: The Billing Reform
A structural change is coming, but not to the rates. Decreto-Lei n.º 161/2026 restructures IUC billing and payment from 1 January 2027: instead of the tax falling due in each vehicle's registration-anniversary month, there will be a single annual centralized settlement, paid in April in instalments. Crucially, there is no rate change for 2026 — only the mechanics of when and how you pay change from 2027. So budget the 2026 figures as normal this year, and expect the April-instalment model from next year.
How and When You Pay Today
For 2026, IUC falls due in the month of the vehicle's first registration and is paid through Portal das Finanças (you can generate the reference online and pay by home banking, ATM/Multibanco or direct debit). Miss the window and interest and penalties accrue, so set a reminder for your registration month.
Common Mistakes
- Assuming IUC and ISV are the same tax. ISV is the one-off entry tax; IUC is the annual bill.
- Using the wrong CO2 table. WLTP-typed and older NEDC-typed cars use different g/km bands — check your car's certificate of conformity.
- Forgetting the diesel component and CO2 levy. On bigger or higher-emission cars these add up.
- Ignoring the registration year. Anything registered from 2010 carries the full 1.15 coefficient.
Getting Help
Most owners can pay IUC themselves once the car is registered. Where people genuinely need help is at the import stage — getting the ISV assessment right, the CO2 typing correct, and the Portuguese matrícula issued so the IUC clock starts cleanly. If you're bringing a car into Portugal, our team handles the legalisation end to end.
Importing a vehicle into Portugal? Our car import service handles the ISV assessment, customs and registration so your car is legal and your IUC starts on the right footing. Check your likely ISV first with our ISV import calculator, and see every figure in this guide on the verified vehicle-tax dataset.
Frequently Asked Questions
IUC (Imposto Único de Circulação) is Portugal's annual road tax, owed every year by whoever owns a vehicle registered in Portugal on the anniversary month of its first registration. It is separate from ISV, the one-off registration tax you pay when a car first enters the Portuguese fleet. For a modern passenger car (Category A), IUC is built from a cilindrada (engine-size) component plus a CO2 component, multiplied by a year-of-registration coefficient, with a diesel surcharge where applicable.
It depends on engine size, CO2 emissions and the year of first registration. As a rough guide for a mid-size petrol car registered from 2010 onward: a 1,600 cm³ car emitting around 130 g/km pays roughly €148 a year (a €63.74 cilindrada band plus a €65.15 CO2 band, multiplied by the 1.15 coefficient). A larger diesel adds the diesel component (from €5.02 up to €68.85 by engine size) and often a higher CO2 band. Check the exact bands on our verified vehicle-tax dataset before you budget.
Full-electric vehicles (BEVs) are exempt from ISV, the one-off registration tax. For IUC, electric and low-emission vehicles benefit from much lower charges than combustion cars because the CO2 component is what drives most of the bill. If cutting your running costs matters, the emissions band is the single biggest lever — a low-CO2 car pays a fraction of what a high-emission one does.
Today, IUC falls due in the month of the vehicle's first registration and is paid through Portal das Finanças. Decreto-Lei n.º 161/2026 restructures IUC billing from 1 January 2027 into a single annual centralized settlement paid in April, in instalments. There is no rate change for 2026 — only the payment mechanics change from 2027.
IUC becomes due once the vehicle is registered in Portugal with a Portuguese plate. During the import and legalisation process — customs clearance, ISV assessment and matrícula — you are dealing with ISV, not IUC. Once the Portuguese registration is issued, the IUC clock starts on that registration month for every year you own the car.