What's legal, from the regulations.

The rule

The Road Vehicles (Construction and Use) Regulations 1986, regulation 32, requires the windscreen and the windows either side of the driver's seat to have a visual transmission for light of not less than 75% for the windscreen and 70% for the other windows, for vehicles first used on or after 1 April 1985. Vehicles first used before that date must have at least 70% on all of those windows.

GOV.UK puts it plainly: the front windscreen must let at least 75% of light through and the front side windows must let at least 70% of light through. There are no rules for tinting the rear windscreen or rear passenger windows.

Sources: legislation.gov.uk, SI 1986/1078 reg. 32 · GOV.UK, "Tinted vehicle windows: the law"

Glass and film together

The regulation measures the window, not the film. Factory door glass is rarely 100% clear; most modern cars sit somewhere between about 75% and 88% before any film is applied. Transmissions multiply, so a "70% film" on 80% glass gives 80% × 70% = 56%, which fails. That is why a "70% front tint" sold as legal usually isn't, and why we meter your glass before fitting anything to the front doors.

Enforcement

Police and DVSA examiners check tint with light meters at the roadside. GOV.UK lists the possible outcomes as a prohibition notice stopping you using the vehicle until the film is removed, a penalty notice, or a court summons. We don't quote fine amounts or penalty points on this page because we could not find them in an authoritative source; anyone who does quote them should be able to cite where from.

The MOT

Tint is not metered at the MOT. The DVSA inspection manual for cars treats tinting as a Minor defect unless the visibility through the swept area of the windscreen or of an obligatory external mirror is seriously affected, in which case it is a Major defect and a fail. Dark rear glass will not fail an MOT; a heavily tinted windscreen can.

Source: DVSA MOT inspection manual, cars and passenger vehicles, section 3.2

Sunstrips

Regulation 32 exempts the part of the windscreen outside the driver's vision reference zone, which is why a sunstrip along the top edge is generally accepted. We could not find an official figure for how deep a sunstrip may be, so we fit them above the swept area of the wipers and no lower.

What this means for you

• Rear side windows and rear screen: any shade, from 70% down to 5%.
• Front side windows: only a near-clear heat-rejection film, and only if the metered glass-plus-film reading stays at or above 70%. We write the reading on your invoice.
• Windscreen: no film in the swept area. Sunstrip above it.
• Already got dark fronts? We remove old film cleanly at £45 per window and refit a legal shade.

This page is general information about the law as published on 4 September 2026, not legal advice. If a regulation changes we update it.