Understanding Car Window Glass Codes: What They Mean and Why They Matter

When looking closely at your car windows, you’ll notice a small section etched with letters, numbers, and symbols—often overlooked, yet incredibly important. These are car window glass codes, and they tell a story about your vehicle’s safety, specifications, and legal compliance. 

Whether you’re a curious car owner, a DIY enthusiast, or seeking auto glass repair or replacement, understanding these codes can help you make more informed decisions. Let us understand what car window glass codes mean, why they matter, and how to read them—especially if you’re thinking about a windshield or window glass replacement.

What Are Car Window Glass Codes?

Car window glass codes are a combination of markings etched or printed onto the corner of automotive glass, usually found on windshields, side windows, and rear windows. These codes provide information about:

• Manufacturer
• Type of glass
• Safety standards compliance
• Tint levels
• Laminated vs. tempered glass
• DOT (Department of Transportation) approval number
• E-code (European standard)
• Manufacturing date and batch code

Why Are Car Window Glass Codes Important?

These small engravings might seem insignificant, but they carry great significance for safety, legal compliance, and quality assurance. Here’s why:

1. Safety Standards

Car window glass must meet strict government safety regulations. The codes indicate that the glass complies with DOT (in the U.S.) or ECE R43 (in Europe) standards. This ensures your glass has passed crash-resistance and shatter-proof tests.

2. Glass Replacement Accuracy

If your car window or windshield gets damaged, referencing the correct glass code ensures that the replacement matches the original specification. This is critical for maintaining structural integrity and safety features like airbags.

3. Legal Tint Compliance

Some codes include details on the level of tint. Certain states and countries have legal limits on how dark your window tint can be. Reading the glass code helps verify compliance.

4. Insurance Claims

For insurance and warranty purposes, having a record of your car window glass codes can simplify the claim process. It confirms OEM (Original Equipment Manufacturer) or equivalent-quality replacement.

Breaking Down the Elements of Car Window Glass Codes

Let’s take a look at a sample car window code and break it down:

SAINT-GOBAIN SEKURIT

DOT 39 AS1 M848

43R-00048 E2

LAMINATED

1. Manufacturer Name

In this case, “Saint-Gobain Sekurit” is the brand of glass used. Other popular manufacturers include Pilkington, Guardian, AGC, and Fuyao.

2. DOT Number

“DOT 39” means the manufacturer is registered with the U.S. Department of Transportation. The number (in this case, 39) is unique to each registered manufacturer.

3. AS Number (American Standard)

The “AS” rating tells us what kind of glass it is:

AS1 – Fully transparent glass (used for windshields)

AS2 – Slightly tinted (used for side and rear windows)

AS3 – Darker tint or reflective (not always legal for driver visibility)

4. Model or Glass Code (M Number)

“M848” is the model or type of the glass. This helps identify the specific shape, tint, and design required if you need a replacement.

5. E-Code (European Standard)

“43R-00048 E2” is the ECE regulation marking. The “E2” indicates the glass complies with European safety standards and was approved in France.

6. Glass Type

If it says “LAMINATED”, it refers to safety glass that holds together when shattered (typically used for windshields). If it says “TEMPERED”, it shatters into small blunt pieces for safety (usually used in side and rear windows).

How to Read the Manufacturing Date Code

Many auto glass pieces include a dot matrix, number ring, or date code to show when the glass was manufactured. This can be useful for:

• Matching OEM specifications
• Detecting manufacturing defects
• Confirming warranty eligibility

Manufacturers use different date formats. For example:

• “10A23” could mean October 2023.
• A “dot” system (e.g., 7 dots on the left, 5 on the right) might indicate July 2015 (7th month of 2015).

OEM vs. Aftermarket: Does the Code Change?

Yes, and here’s how to tell the difference:

OEM Glass

• Comes directly from the vehicle manufacturer or their approved glass supplier
• Contains original DOT and glass code matching the rest of the car
• Usually etched with brand logos (e.g., Ford, Honda, Toyota)

Aftermarket Glass

• Made by third-party manufacturers
• Still has DOT and AS ratings but may lack vehicle branding
• Quality may vary—always check codes to ensure safety compliance

At GlassFixit, we always recommend using OEM or equivalent-quality glass for replacements and ensure that all our glass meets legal and safety standards.

Where to Find Car Window Glass Codes on Your Vehicle

You can usually spot the codes:

• On the lower corner of the windshield (driver or passenger side)
• Near the bottom of side windows
• At the edge of the rear window

Sometimes the etching is faint—use a flashlight or take a photo and zoom in to read it more clearly.

What to Do If Your Window Glass Code is Missing or Damaged

If the etching is unreadable due to scratches or replacements:

• Check the owner’s manual for OEM part numbers
• Ask a professional (like us at GlassFixit!) to decode or match the glass
• Contact the dealership with your Vehicle Identification Number (VIN)

Final Thoughts

Understanding car window glass codes gives you better control over your vehicle’s safety, legality, and quality. Whether you’re replacing a windshield, side window, or rear glass, these markings ensure you’re getting the right fit—without compromising on standards.

At GlassFixit, our technicians are trained to identify, decode, and match all types of auto glass. If you’re in California and need a safe, affordable, and fast glass replacement, we’re here to help!

Book Your Car Glass Inspection Today

Need help identifying your car window glass code or replacing a damaged pane? Contact GlassFixit for a quick, professional solution. We serve customers across San Jose, Santa Clara, and nearby California locations with same-day or next-day service.

📍 Locations:

San Jose Office: 3851 Charter Park Drive, Suite L, San Jose CA 95136

Santa Clara Office: 1250 Norman Ave, Santa Clara CA 95054

📞 Phone: +1 408-564-0419

🕒 Hours: Monday to Friday- 8am to 5pm | Saturday & Sunday- Closed