Is Window Tint Legal in the UK?
In the UK, window tint is legal on the glass behind the driver, but the front windscreen and front side windows must meet minimum light-transmission limits - and most aftermarket front tint does not.
Why?
The rule is the same for every car on UK roads and it comes down to how much light gets through the glass in front of the driver. The front windscreen must let at least 75% of light through, and the front side windows at least 70%. Those two figures are the whole test.
There are no limits at all on the rear windscreen or the rear side windows, so they can be tinted as dark as you like, including near-black film. It is only the front that is restricted.
Most aftermarket films sold as 5%, 20% or 35% put the front windows well under the 70% mark, which makes them illegal to use on the road. Police and DVSA examiners measure tint with a calibrated light meter at the roadside, so it is not a matter of opinion. Too dark and you can be handed a prohibition notice that takes the car off the road until the film comes off, and fitting or selling over-tinted glass is a separate offence.
What decides if it's legal
- Front windscreen: at least 75% of light must pass through.
- Front side windows: at least 70% of light must pass through.
- Rear windscreen and rear side windows: no legal tint limit.
- Measured at the roadside with a calibrated meter; over-tint means a prohibition notice.
| Window | Minimum light through | Dark aftermarket film? |
|---|---|---|
| Front windscreen | 75% VLT | Not road-legal |
| Front side windows | 70% VLT | Not road-legal |
| Rear side windows | No limit | Allowed, any darkness |
| Rear windscreen | No limit | Allowed, any darkness |
Does it depend on your car?
The limits are identical for every car - a hatchback, a saloon or an SUV all face the same 75% and 70% front-glass rule. What changes is the factory glass: some cars leave the showroom with darker privacy glass on the rear (which is fine), but factory front glass already uses up part of your margin before any film goes on.
How other countries treat this
The same modification, judged by four different legal systems.
Common questions
What is the darkest legal tint for the front windows?
The front windscreen must let through at least 75% of light and the front side windows at least 70%, so the darkest legal front film is a very light one that keeps you above those figures. Films sold as 50% can sometimes work on the fronts depending on the factory glass, but anything marketed as 35%, 20% or 5% will put you under the limit and is not road-legal on the front.
Can I tint the rear windows as dark as I want?
Yes. There is no legal tint limit on the rear windscreen or the rear side windows, so you can run film as dark as "limo" black there. The restriction only ever applies to the glass in front of the driver.
Will tinted windows fail an MOT?
Over-dark front glass can fail the MOT, because the tester checks the driver's view through the windscreen and front side windows. Rear tint is not an MOT failure. Separately from the MOT, police and DVSA can measure front tint at the roadside with a calibrated meter and issue a prohibition notice on the spot, so passing an MOT is not the only test that matters.
How is window tint measured?
With a calibrated light meter that reads visible light transmission (VLT) as a percentage. It is an objective number taken at the roadside, not a judgement call, so "it looks fine" is no defence if the meter reads below 75% on the windscreen or 70% on the front sides.
Related guides
Related legality guides
Sources
Sources last reviewed July 2026.
This page is general guidance, not legal advice, on the rules in the UK for window tint. The detail varies by exact vehicle and changes over time - confirm with your insurer and the latest DVSA and GOV.UK guidance before modifying.