Tinted windows are legal in Portugal if the film is homologated, approved in an extraordinary inspection and recorded on the registration certificate. The light let through cannot be below 75% on the windscreen or 70% on the front windows; at the back there is no limit. Without the inspection and entry, you risk a €250 to €1,250 fine and seizure of the car.
This guide explains what the law allows, the limits, how to make your windows legal at the IMT, what it costs and what to check when you buy a used car with tinted windows.
Tinted windows: what the law says
According to the IMT, the rules on tinted windows come from Decree-Law 392/2007, amended by Decree-Law 193/2009. It allows coloured films on the windows of light passenger and goods vehicles, as long as they are homologated and carry a legible, indelible homologation mark.
A film counts as a modification of the vehicle. So you may only drive with it once the car has passed an extraordinary inspection and the change is recorded on the registration certificate (article 25 of the glass regulation).
How much light must pass through
Article 24 of the safety glass regulation (DL 40/2003, as worded by DL 392/2007) sets the light transmission factor, measured from outside in, on glass with the film fitted on the inside:
- windscreen: may not be below 75%;
- side windows in front of the B-pillar (the front doors): may not be below 70%;
- rear windows: the law sets no darkness limit, according to Caetano.
So rear windows may be darker than the front ones, as long as the film is homologated and the change approved and recorded. With film on the rear window, two exterior rear-view mirrors are mandatory, and film is not allowed on windows marked as emergency exits (article 22 of the regulation).
Factory-tinted glass or film: what is the difference
There are two cases. In many cars, especially SUVs and vans, the rear windows come tinted from the factory. They are standard glass and, according to Postal, count as homologated even if the registration certificate does not say so.
The other case is film fitted after purchase, and that is the one that needs to be made legal. So when buying, ask whether the tint is original: with standard glass there is nothing to record, with film the registration entry is mandatory.
How to make tinted windows legal at the IMT
The process, according to the IMT, is:
- homologated film: with the national homologation mark, or one from another Member State treated as equivalent, clearly legible on the glass;
- fitting: Caetano says it may only be done by a company with an Application Certificate;
- extraordinary inspection at a category B inspection centre;
- a €150 fee to the IMT, and the entry on the registration certificate.
The inspection approval sheet is valid for 90 working days, so have the change recorded without delay. The IMT publishes a list of films with recognised homologation, and it is worth checking the film against it before you buy.
How much it costs to make tinted windows legal
The only official fee the IMT states is €150. Caetano also estimates about €100 for the extraordinary inspection, €30 for changing the registration certificate and up to about €200 to fit the film, depending on the workshop, for a total above €450. These are September 2023 figures: confirm current prices and what each one includes.
Fine for illegal tinted windows
The Highway Code has no fine just for «dark windows». Modifying the vehicle without authorisation is punished under article 115 with a fine of €250 to €1,250 and seizure of the vehicle until it passes an extraordinary inspection, unless a more serious penalty applies. See the text in the Highway Code.
Periodic inspections also check for air bubbles or peeling film that harm the driver's visibility. For what else is checked, see our guide to the car inspection. And see the mandatory stickers on the car windscreen.
Exceptions
The rules on films do not apply, according to the IMT, to plastic films on the windows of security-force and judicial-authority vehicles, the cargo area of light goods vehicles and the sanitary compartment of ambulances.
Buying a used car with tinted windows
When you see a car with dark windows, read the registration certificate: the film must be recorded there. Also ask for the homologation mark and the invoice. Look for bubbles or peeling film, and check that the front windows let you see the interior clearly. If there is no entry, making it legal is on you.
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Frequently asked questions
Are tinted windows legal in Portugal?
Yes, if the film is homologated, the car passes an extraordinary inspection and the change is recorded on the registration certificate.
What percentage of tint is allowed?
The windows must let through at least 75% of light on the windscreen and 70% on the front side windows. At the back, the law sets no darkness limit, but requires two exterior mirrors.
What is the fine for tinted windows?
There is no specific fine. Unauthorised modification of the vehicle is punished with a fine of €250 to €1,250 and seizure until it passes an extraordinary inspection.
How much does it cost to make tinted windows legal?
The IMT fee is €150. The inspection, the registration entry and fitting the film add to it, and Caetano estimated more than €450 in total in 2023.
Do factory-tinted windows need to be made legal?
No, according to Postal: factory-tinted glass counts as homologated.
