Reading Glass Markings: The Complete Decoder

Where it is and how it is made

The marking is found in a corner of the glass, usually the lower one, and is made with screen-printed ceramic inks that vitrify during glass processing, becoming part of the sheet. This is why it doesn't scratch off, fade, and survives decades of washing: it is not a layer applied to the glass; it is inside the glass.

The block contains information that addresses different needs — commercial, European regulations, other markets' regulations — and therefore it may seem redundant: the same glass might simultaneously carry markings for Europe, the United States, and other countries because it was produced on a line that supplies different markets. This is not an error nor a sign of questionable origin: it's industrial normalcy.

A clarification worth making immediately, as it is the source of many misunderstandings: the Eurocode is not on the marking. The commercial code used to order replacements — explained in the dedicated guide — lives on labels and in catalogs, not on the screening. The marking is the legal identity; the Eurocode is the commercial one. Both are needed and are not interchangeable.

The symbols, one by one

The manufacturer's logo

The name or logo of the glass manufacturer — not the carmaker. This is the most immediately useful information for those needing to order a replacement: as explained on the page about original, equivalent, or used glass, finding the equivalent from the same manufacturer that supplied the car at the factory is the simplest way to get an identical glass.

On OEM glasses, next to the glass manufacturer's logo, the automaker's logo may also appear: it is the mark of the original replacement, and its absence on an equivalent glass does not indicate any difference in specification — just a different distribution channel.

European approval marking

The most legally significant block, recognizable by two elements:

• The letter E inside a circle, followed by a number: certifies approval according to international regulations, with the number identifying the country that issued the approval — not the country of production. It's a distinction that confuses many: a glass with E1 is not necessarily German; it is approved in Germany.
• The code 43R followed by an approval number: referring to the international regulation on safety glass, detailed on the approval page.

This marking is what makes a glass legally mountable on a vehicle operating in Europe. Its absence is, by itself, a problem: a glass without approval is not a cheap replacement; it is a non-usable replacement.

The type of glass

Indicated with explicit labels in English — TEMPERED or TOUGHENED for tempered glass, LAMINATED for laminated glass — and, in markings following international classifications, also with Roman numerals that distinguish the glass categories according to construction characteristics and light transmission. In the most common classifications, for example, low numbers identify types of laminated windshield with different treatments, while other numbers distinguish glasses based on light transmission — above or below the threshold relevant for driver visibility.

For practical purposes, the clear label is what counts: tempered or laminated answers the question at the time of ordering and for safety — explained on the page about tempered glass, where it is shown why knowing which side windows are tempered means knowing from where one could exit in an emergency.

Markings for other markets

On glasses produced for global lines, one often also sees:

• DOT followed by a number: the marking for the United States market, where the number identifies the manufacturer and factory.
• AS1, AS2, AS3: the American classification by position and light transmission, with AS1 reserved for positions requiring maximum transparency.
• Compliance initials from other countries, for Asian and South American markets.

Their presence on a glass sold in Europe is, as said, industrial normalcy — and sometimes a useful indicator of the manufacturer.

The date code: reading the age of glass

The most curious detail of the entire marking, and one of the most useful. Every glass carries an indication of the production period, encoded in a way that appears cryptic but follows a simple logic.

The most widespread system uses a digit for the year — usually the last digit — along with one or more dots indicating the month. The classic convention: dots placed before the digit and those placed after have different meanings, and their combination covers all twelve months with few symbols. The practical reading: count the dots and see on which side they are relative to the year digit.

Since conventions may vary among manufacturers, the value of this information is not in month precision but in comparison. And this is where it becomes truly useful:

• On a used car: if three glasses have dates consistent with each other and with the registration, and one is visibly more recent, that glass has already been replaced. This is valuable information during a purchase — not necessarily negative but worth knowing — and explains why the glass may not be the factory variant.
• Before ordering: a glass previously replaced might differ from the original variant, and what matters is what's mounted, not what's indicated on the chassis.
• On used glasses: the date indicates the real age of the glass, which accumulates surface micro-abrasions over the years even if remaining intact.

There's also a more subtle use appreciated by vehicle evaluators: all original glasses with consistent dates indicate an accident-free career, whereas multiple glasses replaced at the same time suggest an event — hail, break-ins, impacts. This isn't proof but data, visible to anyone who knows where to look.

Verification upon delivery: five minutes before installing

Here's the most important application of all this: checking the received replacement before picking up the tools. Discovering a mistake with the glass installed costs double the effort; discovering it just after opening the package costs a message to the seller.

1. The label: replacement glasses come with adhesive labels that show the Eurocode and the manufacturer's code. These are to be precisely matched with the order. This is the main check, resolving most of the verifications.
2. The screen-printed marking: verify that the type of glass matches expectations — tempered or laminated as established by the pre-order checklist — and ensure the approval is present and readable.
3. The tint: view the glass edge-on, and mentally compare (or use a photo) with the car's existing glasses. It's the most visible mistake and the one best caught before installation.
4. The pre-arrangements: electrical contacts where they need to be, holes and fixtures in their places, potential pre-assembled profiles matching.
5. The integrity: go around the perimeter with a gloved finger and good light, checking for nicks on edges — which on a newly arrived glass indicate transport damage, to be reported immediately as described in the shipping guide.
6. The overall dimensions: without millimeter precision, visually compare with the door opening or twin glass to catch gross errors — a glass from another generation or another body type is recognizable at a glance.
7. The side: the final, simple yet crucial check. The glass is ideally presented at the door opening before mounting to ensure the curvature matches.

One maneuver simplifying everything: photograph the new glass's label and marking before mounting. It helps if problems arise (provides proof of what was delivered), it's useful for the next replacement, and it updates the photographic archive of your glasses suggested on the Eurocode page.

Reconstructing the identity of glass from the marking

The reverse from verification: you have glass (or a fragment) and need to determine what to order. This is the typical situation after damage, and the marking is the starting point.

The sequence

1. Photograph the marking clearly: side lighting, dark background behind the glass if possible, focus on the screening. This step makes everything else possible — and should be done before vacuuming the granules.
2. Extract the useful information: manufacturer’s logo, type of glass, any symbols indicating special features, date code.
3. Cross-reference with the vehicle: plate or VIN determine the model, the marking narrows down the variant — since it says what type of glass and who produced it.
4. Find the Eurocode through the catalog, which is the code used to order.
5. Confirm with seller in doubtful cases, attaching the marking photo to the file as described in the identification guide.

The case of the fragment

After a breakage, the corner with the screening is often the only piece retaining information. It's worth methodically searching for it among the fragments: being the most inked area, it tends to remain identifiable even in small shards. Those who recover it hold the direct witness of the lost glass; those who vacuum it along with everything else must reconstruct everything by deduction — possible, but more time-consuming.

The operational advice, repeated throughout this section because it saves the most time: before cleaning, find and keep the fragment with the marking. In a resealable bag, alongside the photos. Ten seconds that give certain identification.

The marking vocabulary

Screen printing (marking)

The block of symbols printed with ceramic inks in the corner of the glass and vitrified during production. It is designed to be permanent and constitutes the legal identity of the glass.

Approval mark (E with a circle)

The letter E in a circle followed by the number of the country that issued the approval — not the country of production. Certifies compliance with international regulations on safety glass.

43R

Reference to the international regulation on vehicle safety glass, followed by the specific approval number for that type of glass.

DOT

The marking required by the United States market, followed by a number identifying manufacturer and plant. Its presence on a European glass indicates only a production line aimed at multiple markets.

AS1, AS2, AS3

The United States classification for glass by position and light transmission, with the highest category reserved for positions requiring maximum transparency.

Date code

The indication of the production period, typically a digit for the year accompanied by dots that code the month according to conventions that vary between manufacturers.

OEM glass

The glass mounted at the factory, recognizable by the presence of the carmaker's logo next to the glass manufacturer's logo. Its absence indicates an independent aftermarket replacement, not a lower specification.

Feature symbols

The additional markings some screenings use to indicate special features of the glass — treatments, functional layers, pre-arrangements. They are not standardized like regulatory symbols and vary between manufacturers.

Monogram

The logo or initials of the glass manufacturer. Not to be confused with the potential carmaker's logo, which identifies the original replacement channel.

Three real readings

The glass that told a hail story

Sedan used during appraisal with a private seller, declared "never crashed." The potential buyer, having read something about markings, walks around the car checking the glass corners: windshield, rear window, and rear side windows show production dates much later than registration and among themselves consistent, while the four side windows are original. The picture is clear: an event affecting horizontal and more exposed surfaces — the typical signature of hail — with replaced affected glasses.

It's not a dramatic discovery nor a deal breaker: hail is a weather event, and the glasses have been replaced. But it’s information the seller hadn’t mentioned, prompting two extra questions — about the bodywork, for example. All derived by looking at four glass corners for two minutes.

The replacement discovered before installation

Front glass ordered for a compact car, regular delivery. The owner opens the package and, following the procedure, compares the label with the order: Eurocode matches. Then looks at the screening and finds tempered, whereas the car — checked with the checklist — had laminated acoustic fronts. Contacts the seller with photos: the ordered code was actually for the basic variant, and the mistake originated from the initial choice.

No discussion replacement, a few days lost. But the point is another: if installed before checking, the difference would have been discovered on the highway a month later, with the glass already installed and return no longer feasible.

The fake "original" glass

Used car bought from a private seller, presented with "all original glass." A look at the markings: three glasses show the manufacturer's monogram and the carmaker's logo, one only the manufacturer's monogram. That glass is an equivalent mounted during a previous replacement — perfectly legitimate and technically equivalent, as explained on the dedicated page, but different from what was declared.

The value of observation lies not in judgment on the glass, which is perfectly good: it’s in the fact that the marking is a document that cannot be rewritten, and it tells the car's story better than any verbal claim.

What the marking does not say

To use this tool well, it's important to know its limitations, which are three and are regularly misunderstood.

How to photograph a marking legibly

It seems a detail, but it isn’t: an unreadable photo of the screening is as good as no photo, and practically is why many requests to sellers require a second round of messages. The marking is black on transparent glass — the worst combination for any camera.

The four measures that solve it:

• A light background behind the glass: a sheet of white paper, a hand, a light towel placed on the opposite side. This trick changes everything: without a background, the camera focuses on what's behind the car; with the background, it focuses on the screening.
• Side lighting instead of front lighting: direct flash produces a reflection that cancels out the very area of interest. Better natural side light, or a torch held aside.
• Clean glass: a cloth wipe on the area because dust and halos photograph better than characters.
• Correct distance: close enough to read the characters, yet far enough to frame the entire block. Better two photos — one overall and one detail — than one compromise.

Those doing this operation for the first time often discover that the marking, when well observed, contains more information than noticed with the naked eye: small characters, minor symbols, and initials that disappear from a distance. Photography is not just for sharing — it's for seeing.