For as long as IUC has existed, the month you pay it has been the month your vehicle was first registered. Decreto-Lei n.º 161/2026 ends that. From 2027 the vehicle tax has a fixed calendar for everyone, and the year of the change has its own separate rules.
What happens today, through 2026
IUC is due in the month of the vehicle's first registration. A car registered in March is taxed every March; one registered in November, every November. It is why nobody can tell you when your IUC is due without asking about your car.
What changes from 2027
The anniversary month disappears. In the settled regime IUC becomes due in April, splitting into instalments above certain amounts — but that schedule starts in 2028. 2027, the first year without the anniversary month, has a calendar of its own.
| Annual amount | When you pay |
|---|---|
| Up to €100 | April |
| More than €100 | April and October |
| More than €500 | April, July and October |
2027 is not the new rules either
There is a second thing worth knowing about the thresholds, and it is the part that will surprise people with more than one vehicle: the instalment bands are read against the taxpayer's total annual assessment, not against each vehicle separately. Three cars that would each sit under a threshold can add up to a bill that does not.
What has not changed
- Electric vehicles remain exempt.
- A new vehicle's first IUC is still due within 30 days of registration.
- Through 2026 — including the whole of this year — the registration anniversary month still governs.
The IUC calculator works out the amount for a given vehicle, which is what decides which of the three instalment bands you land in.
When is IUC due in Portugal?
Through 2026, in the month the vehicle was first registered. The anniversary month is abolished from 2027, but the April schedule with instalments above €100 and €500 starts in 2028. In 2027 itself the tax falls in October, splitting into July and October above €500.
Is the IUC instalment threshold per vehicle?
No. The bands are applied to the taxpayer's total annual assessment, so several vehicles that would each fall below a threshold can together exceed it.
When do I pay IUC on a newly registered car?
Within 30 days of registration. That has not changed and is separate from the annual cycle.
Are electric vehicles exempt from IUC?
Yes, electric vehicles remain exempt.