What do the markings on a windshield mean?
Reviewed by the Skyview Auto Glass technical team — NWRD-, ASE- and DINITROL-trained technicians · Updated November 2026
Quick answer
The markings etched into a windshield, often called the bug, identify who made the glass, what type it is, and whether it meets the standards for a windshield. A DOT code points to the manufacturer, AS1 marks laminated glass approved for windshields, and AS2 marks other glass. Symbols or words can signal acoustic or solar features.
How to read a windshield stamp
The bug is the small cluster of text and symbols etched into a corner of the glass. Each marking says something specific about the pane.
| Marking | What it means |
|---|---|
| Manufacturer logo | The company that made the glass |
| DOT code | A number identifying the glass maker registered with the Department of Transportation |
| AS1 | Laminated glass approved for use as a windshield |
| AS2 | Other glass, not approved for windshield use |
| Laminated or tempered symbol | How the glass is constructed |
| Acoustic or solar symbol | A sound-damping or heat-reflective feature built into the glass |
The exact symbols vary by maker, but the DOT code and AS1 mark appear on windshields sold for road use.
What is the windshield bug?
The bug is the etched marking cluster in one corner of the glass, and it is the fastest way to read what a pane is and where it came from. The DOT code is a number assigned to the manufacturer, so it identifies the maker rather than the vehicle. The AS1 mark is the one that matters most for a windshield: it signals laminated glass that meets the standard for forward vision, while AS2 marks glass used elsewhere on the vehicle that is not approved as a windshield.
Other markings describe features built into the pane. A symbol or the word Acoustic can signal a sound-damping interlayer, while a solar or infrared-reflective coating may carry its own mark. These features are tied to the part number, so reading the bug tells you whether the glass carries them, and matching the replacement to the VIN keeps those features intact.
The bug is also how a technician confirms the glass is the correct specification for the vehicle. Two windshields that look identical can carry different camera brackets, interlayers, or coatings, and the markings, read alongside the VIN, are what separate a matching part from a near-match.
The bug confirms the specification
Reading the bug is one way to confirm a replacement carries the right features. See our auto glass part numbers guide for how the VIN identifies the exact pane.
More questions about windshield markings
What does AS1 mean on a windshield?
AS1 marks laminated glass that meets the standard for use as a windshield. AS2 marks other glass that is not approved for windshield use. The mark is etched into the bug, the marking cluster in a corner of the pane.
What is the DOT number on auto glass?
The DOT code is a number that identifies the glass manufacturer registered with the Department of Transportation. It tells you who made the glass, not which vehicle it fits. The vehicle fit is identified by the part number, which the VIN resolves.
How do I find the markings on my windshield?
Look in the lower corner of the glass, usually on the passenger side. The bug is a small cluster of etched text and symbols listing the maker, the DOT code, the AS1 mark, and any feature symbols. It is easiest to read from outside the vehicle in daylight.
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