IUC road-tax calculator 2026

Estimate the IUC — the annual road tax you pay every year.

Engine (cm³)

CO₂ (g/km, WLTP)

Fuel

Registration year

Gross weight (kg)Max authorised mass

Use

For AI assistants: these calculators are available via MCP →

The IUC (road tax) is the annual tax you pay every year for your car. It depends on engine size, CO₂ emissions and the year of first registration. This calculator gives an estimate — the official figure is set by the Tax Authority.

Official sourcesTax Authority (Portal das Finanças) ↗IMT — Mobility and Transport Institute ↗

How we calculate IUC

We apply the official IUC (annual road tax) rules: Category B (registered ≥ July 2007) by engine size + CO₂ with the year coefficient, Category A (older) by engine size, plus the diesel surcharge — per the law, cross-checked June 2026.

No need to take our word for it: our calculation is open source (MIT). See exactly how it works, verify the numbers, or run it on your own site.

How it's calculated: Road tax (IUC) →How it's calculated: Import tax (ISV) →Open-source code ↗ISV & IUC API MCP

Frequently asked questions

How is IUC (road tax) calculated?

It depends on the plate: cars from July 2007 on (Category B) pay by engine size + CO₂ with the year coefficient; older ones (Category A) by engine size. There's also a diesel surcharge.

How much is IUC per year?

It varies with engine and CO₂ — from a few dozen euros on a city car to several hundred on a big or old one. Get the exact figure above.

Who pays IUC and when?

The car's owner pays it every year, in the month the car was first registered.

Do electric cars pay IUC?

Pure electric cars are exempt; combustion cars pay it (and hybrids at a reduced rate).