How this works
For a category B passenger car (first registered from July 2007), the IUC is built from three parts: an engine-size charge, a CO2 charge (plus a surcharge above certain brackets) and a coefficient that loads more recent cars. You add the engine-size part to the CO2 part, multiply by the year coefficient, and — only for diesel — add a further charge at the end. The 2026 rates match 2025.
- 1
Engine-size charge
Four 2026 brackets: up to 1250 cc = €31.77; 1251–1750 = €63.74; 1751–2500 = €127.35; over 2500 = €435.84.
- 2
CO2 charge (+ surcharge)
Pick NEDC or WLTP. WLTP e.g.: up to 140 = €65.15; 141–205 = €97.63; 206–260 = €212.04 (+€31.77); over 260 = €363.25 (+€63.74).
- 3
Age coefficient
Multiplies the running sum: 2007 = 1.00; 2008 = 1.05; 2009 = 1.10; 2010 or newer = 1.15.
- 4
Diesel surcharge
Diesel only, added at the end: up to 1250 = €5.02; 1251–1750 = €10.07; 1751–2500 = €20.12; over 2500 = €68.85.
Frequently asked
Which category is my car in?
For light passenger cars it depends on the first registration date. Up to 30 June 2007 it is category A (engine size only). From 1 July 2007 it is category B (engine size + CO2, with an age coefficient). This calculator handles category B; for A I point you to the official rate by engine size.
Where do I find my engine size and CO2?
On the vehicle registration document (DUA): engine size is field P.1 and CO2 is field V.7. Note: since 2018/2019 CO2 stopped being printed on many new cars’ DUA — if so, check the COC (certificate of conformity) or the manual.
NEDC or WLTP — which do I pick?
It is the emissions test standard. Rule of thumb: new cars up to 2017 are NEDC; 2018 and 2019 are a transition (check the paperwork); from 2020 they are WLTP. The CO2 bracket differs by standard, so pick the one shown on your car’s COC.
Why does diesel pay more?
Category B diesel cars first registered from July 2007 carry an extra charge, introduced in 2014 and still in force in 2026. It is added at the end, after the age coefficient, and varies with engine size (from €5.02 to €68.85).
Is this exactly what I will pay?
It is a reliable estimate for a normal category B passenger car. The official figure is the one on the Portal das Finanças, which applies exemptions (disability, taxis, classics, etc.) and cases this tool cannot know. Always confirm there before paying.
DISCLAIMER
Estimate for category B passenger cars (registered from July 2007), using the 2026 table. It does not handle exemptions (disability, taxis, classics), plug-in hybrid edge cases or other categories. The amount you owe is always the one on the Portal das Finanças. Not tax advice.