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IUC Calculator (Portuguese Road Tax)

How much IUC will you pay this year? This calculator estimates Portugal's annual vehicle circulation tax (IUC) for Category B light passenger cars (first registered from July 2007), based on engine displacement, CO₂ emissions, the year of first registration and the fuel. See the amount and how it is reached, component by component.

For light passenger cars first registered from July 2007 (Category B). The amount depends on engine displacement, CO₂ emissions, the registration year and the fuel. 2026 tables.

Annual IUC
€148.22
CO₂ component
€65.15

How the IUC is reached

Displacement component€63.74
CO₂ component€65.15
Sum of components€128.89
× Year coefficient (1.15)€148.22
= Annual IUC€148.22

Educational estimate, not financial advice. Covers Category B (light passenger cars registered from July 2007); it does not cover Category A (earlier cars) or motorcycles, goods vehicles, boats or aircraft.

Video: how to use the calculator

What IUC is and who pays it

The Imposto Único de Circulação (IUC) is an annual tax on vehicles, owed by whoever owns the vehicle on 1 January each year. It replaced the old "car stamp". The amount depends on the vehicle category: this calculator covers Category B: light passenger and mixed-use cars first registered (in Portugal, the EU or the EEA) from 1 July 2007, which are the vast majority of cars on the road.

How it is calculated (Category B)

Category B IUC adds two components (one for engine displacement (in cm³) and one for CO₂ emissions (in g/km)) and multiplies the total by a coefficient that rises with the age of the car (1.00 for 2007 up to 1.15 from 2010). For cars first registered from 2017, the two highest CO₂ bands also pay a CO₂ surcharge (part of the component, so it is multiplied by the coefficient too). Diesel cars then pay a further surcharge based on displacement. As a formula: IUC = (displacement component + CO₂ component [+ CO₂ surcharge if registered ≥ 2017]) × year coefficient + diesel surcharge.

WLTP, NEDC and exemptions

The CO₂ component is read from a different table depending on the homologation standard: NEDC for older cars and WLTP for cars homologated from around 2018 (the g/km thresholds differ; the euro amounts are the same). The emissions figure is on the car’s registration document. 100%-electric Category B cars are exempt from IUC.

Worked example

A petrol car of 1,600 cm³, with 130 g/km of CO₂ (WLTP) and first registered in 2018: the displacement component is €63.74 (the 1,251–1,750 cm³ band) and the CO₂ component is €65.15 (≤ 140 g/km on WLTP), adding up to €128.89. Multiplied by the 1.15 coefficient (registered from 2010), that gives an annual IUC of €148.22. Being petrol, there is no diesel surcharge. An equivalent diesel would also pay the relevant surcharge.

Frequently asked questions

How is a car’s IUC calculated in 2026?
For Category B (light passenger cars registered from July 2007), you add the displacement component and the CO₂ component, multiply by the registration-year coefficient (1.00 to 1.15) and, for diesel cars, add a surcharge based on displacement. The 2026 tables keep the 2025 values.
What makes the IUC vary?
Engine displacement (cm³), CO₂ emissions (g/km), the year of first registration (age coefficient) and the fuel. Newer cars, with more displacement or higher emissions, pay more; diesel cars pay a surcharge.
Do electric cars pay IUC?
100%-electric Category B cars are exempt from IUC. Hybrids are not exempt: they pay based on their displacement and emissions, like any other car in the category.
What is the difference between the NEDC and WLTP tables?
They are two methods of homologating CO₂ emissions. Older cars use the NEDC table and cars homologated from around 2018 use WLTP. The g/km bands differ (WLTP is stricter), but the euro amounts for each band are the same. Use the standard shown on your car’s registration document.
When is IUC paid?
IUC is due every year in the month of the vehicle’s registration anniversary and can be paid on the Portal das Finanças or at a tax office. It is owed by whoever owns the car on 1 January.

Related calculators & reading

Sources

Author: Thorben Rasmus Idel · Reviewed by: Nahar Geva · Last reviewed: 2026-05-31