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How to Read Windshield Markings: DOT Codes, AS Ratings, and Date Stamps
Where to Find the Windshield “Bug” (Stamp) and What It Identifies
Most windshields have a small cluster of markings etched into the glass called the "bug" or stamp. You will usually find it low on the driver or passenger side, near the corner, where it's visible but does not distract from the road. That stamp is more than branding—it is the windshield's ID card. It typically includes the glass maker's logo, a "DOT" code that identifies the prime glazing manufacturer, and a safety rating (such as AS1) that indicates the glazing classification used on public roads. Many stamps also include additional codes for part family, glass type (laminated vs tempered), and feature symbols such as acoustic laminate or solar coating. In the United States, the DOT marking is part of the required certification markings for automotive glazing, which is why you will see it on both original and replacement glass. Knowing where to look helps you make smarter decisions: you can compare markings on both sides of a vehicle, confirm whether a windshield has been replaced before, and provide accurate information when ordering glass or filing an insurance claim. At Bang AutoGlass, we often ask customers to snap a clear photo of the bug—because a single picture can confirm the right glass options and prevent delays caused by ordering the wrong configuration.
DOT Code Explained: Manufacturer ID and Compliance Basics
The DOT code on your windshield is often misunderstood. "DOT" does not mean the glass was made by the Department of Transportation; it means the glazing manufacturer is certifying that the glass meets U.S. glazing requirements and is marked with a manufacturer code that NHTSA assigns. Under FMVSS 205, the prime glazing manufacturer adds the "DOT" symbol plus its unique code mark to the required stamp, which makes the source of the glass traceable if there is ever a safety question. In practice, the DOT number helps identify who produced the glass and, in some cases, where it was made, but it is not a guarantee of being "OEM" or a direct quality ranking. Two windshields can both be compliant and still differ in features like acoustic interlayers, coatings, or bracket designs. That is why we treat the DOT code as one piece of a larger identification process. If you are curious, the manufacturer code can often be cross-referenced through public databases and manufacturer listings, and it can help confirm whether a windshield has been replaced with a different brand than factory. For ordering replacement glass, Bang AutoGlass uses the DOT stamp as a verification tool—paired with VIN-based part lookup—so the glass you receive matches the right fit, options, and certification markings.
A windshield DOT code is a certification marking under U.S. glazing rules that identifies the prime glazing manufacturer through a unique NHTSA-assigned number.
DOT numbers help trace who made the glass, but they do not guarantee OEM quality, so options and fitment still need to be verified.
Pairing a clear photo of the bug with VIN-based lookup prevents ordering the wrong windshield when multiple bracket and feature variations exist.
AS1 vs AS2 vs AS3: What the Safety Rating Means
The "AS" rating in the windshield bug refers to the safety glazing classification defined in the ANSI/SAE Z26.1 glazing standard that is referenced by U.S. law in FMVSS 205. Think of it as the glass's approved use category, tied to testing requirements and—importantly—light transmission. AS1 is the designation you will typically see on front windshields because it allows the high visible light transmission needed for safe forward visibility. AS2 is commonly used for side windows and rear glass, where different light transmission limits are permitted. AS3 generally indicates darker glazing often associated with privacy glass and is not appropriate for a front windshield in normal passenger vehicles, because it transmits less light. While the stamp does not tell you everything about the glass (for example, whether it is acoustic or solar), it quickly confirms that the glazing belongs in the location where it is installed. If you ever notice an unusual rating on a windshield—especially a rating not consistent with a front windshield—treat it as a red flag and have it checked. At Bang AutoGlass, we verify the AS rating during part confirmation so the replacement glass meets the correct glazing classification for the application, preserves visibility, and keeps the vehicle compliant with safety standards.
Windshield Date Codes: How to Tell the Build Month and Year
Many windshields include a date code that indicates when the glass itself was manufactured, which can help you understand whether the glass is likely original to the vehicle or a later replacement. There is no single universal "one format" that every manufacturer uses, but a very common system combines a single digit for the year with a row of dots (or sometimes small marks) that represent the month. In that common format, the digit corresponds to the last number of the year (for example, "4" could be 2014 or 2024), and the number and placement of dots are used to narrow down the month, sometimes with dots on one side meaning the first half of the year and dots on the other side meaning the second half. Because vehicle model years and registration dates provide context, you can usually tell which decade the code is referring to. The key is to treat the date code as a clue, not the only proof—especially on older vehicles or in cases where the stamp is partially worn. If you are trying to match glass for an appearance restoration, date codes can be very useful. For everyday replacement, Bang AutoGlass focuses on the VIN, part number, and feature symbols, and we use the date code mainly as supporting information to confirm what is currently installed.
Many date codes use a year digit plus dots or marks for the month, helping you estimate when the windshield glass was manufactured.
Because date-code formats vary by manufacturer, use the vehicle model year and other stamp details to interpret the decade correctly.
Date codes are best used as supporting evidence for originality or restoration, while VIN, part number, and feature icons should drive replacement selection.
Other Symbols You May See: HUD, Acoustic, Solar, Heated, Rain Sensor
Beyond DOT and AS ratings, many windshields carry feature symbols that matter for comfort and safety. A HUD (head-up display) marking may indicate a special laminate or "wedge" layer engineered to prevent double images when the projection reflects off the glass. Acoustic windshields often use an additional sound-damping interlayer; they are great for cabin quiet, but they should be matched correctly so the vehicle's noise performance stays consistent. Solar or UV markings can signal a coating that reduces heat and glare—helpful in bright climates and for protecting interiors. Heated windshield indicators may refer to a full heating element, a heated wiper park area, or embedded antenna elements; these options change both the wiring interface and what you see in the glass. You may also see icons related to a rain/light sensor, which usually means the glass includes a dedicated sensor pad or mounting location that must line up precisely with the sensor housing. None of these features are "nice-to-have details" when it is time to replace the glass; they are part of how the vehicle was built. If a replacement windshield is missing a HUD wedge, for example, the HUD can appear blurry or duplicated. At Bang AutoGlass, we use these symbols—along with VIN verification—to confirm you receive the right glass the first time, with all the features your vehicle is designed to use.
How to Use Markings to Order the Correct Replacement Glass
If you need replacement glass, the fastest way to avoid reorders is to treat the windshield markings as a starting point for a complete match. First, take a clear photo of the bug and any feature icons, plus a wide photo of the full windshield so a shop can see the tint band, camera window, and mirror area. Next, provide the VIN, because VIN-based catalogs link your exact trim level and option content to the correct glass part number. The markings help confirm what is installed today—brand, glazing rating, and feature clues—but they do not always identify every variation, especially on newer vehicles with multiple camera brackets or HUD configurations. A professional shop will cross-check the stamp with the required options (ADAS, rain sensor, heated elements, acoustic laminate) and inspect the mounting hardware to ensure the new glass will accept the existing brackets and trim without gaps. This is also the moment to plan for ADAS calibration: if your windshield has a camera module, ordering the correct glass and scheduling calibration should happen together, not as an afterthought. Bang AutoGlass uses a "verify, then order" process—VIN lookup plus stamp confirmation—so your replacement glass fits correctly, seals quietly, and supports all safety systems as intended.
Services
How to Read Windshield Markings: DOT Codes, AS Ratings, and Date Stamps
Where to Find the Windshield “Bug” (Stamp) and What It Identifies
Most windshields have a small cluster of markings etched into the glass called the "bug" or stamp. You will usually find it low on the driver or passenger side, near the corner, where it's visible but does not distract from the road. That stamp is more than branding—it is the windshield's ID card. It typically includes the glass maker's logo, a "DOT" code that identifies the prime glazing manufacturer, and a safety rating (such as AS1) that indicates the glazing classification used on public roads. Many stamps also include additional codes for part family, glass type (laminated vs tempered), and feature symbols such as acoustic laminate or solar coating. In the United States, the DOT marking is part of the required certification markings for automotive glazing, which is why you will see it on both original and replacement glass. Knowing where to look helps you make smarter decisions: you can compare markings on both sides of a vehicle, confirm whether a windshield has been replaced before, and provide accurate information when ordering glass or filing an insurance claim. At Bang AutoGlass, we often ask customers to snap a clear photo of the bug—because a single picture can confirm the right glass options and prevent delays caused by ordering the wrong configuration.
DOT Code Explained: Manufacturer ID and Compliance Basics
The DOT code on your windshield is often misunderstood. "DOT" does not mean the glass was made by the Department of Transportation; it means the glazing manufacturer is certifying that the glass meets U.S. glazing requirements and is marked with a manufacturer code that NHTSA assigns. Under FMVSS 205, the prime glazing manufacturer adds the "DOT" symbol plus its unique code mark to the required stamp, which makes the source of the glass traceable if there is ever a safety question. In practice, the DOT number helps identify who produced the glass and, in some cases, where it was made, but it is not a guarantee of being "OEM" or a direct quality ranking. Two windshields can both be compliant and still differ in features like acoustic interlayers, coatings, or bracket designs. That is why we treat the DOT code as one piece of a larger identification process. If you are curious, the manufacturer code can often be cross-referenced through public databases and manufacturer listings, and it can help confirm whether a windshield has been replaced with a different brand than factory. For ordering replacement glass, Bang AutoGlass uses the DOT stamp as a verification tool—paired with VIN-based part lookup—so the glass you receive matches the right fit, options, and certification markings.
A windshield DOT code is a certification marking under U.S. glazing rules that identifies the prime glazing manufacturer through a unique NHTSA-assigned number.
DOT numbers help trace who made the glass, but they do not guarantee OEM quality, so options and fitment still need to be verified.
Pairing a clear photo of the bug with VIN-based lookup prevents ordering the wrong windshield when multiple bracket and feature variations exist.
AS1 vs AS2 vs AS3: What the Safety Rating Means
The "AS" rating in the windshield bug refers to the safety glazing classification defined in the ANSI/SAE Z26.1 glazing standard that is referenced by U.S. law in FMVSS 205. Think of it as the glass's approved use category, tied to testing requirements and—importantly—light transmission. AS1 is the designation you will typically see on front windshields because it allows the high visible light transmission needed for safe forward visibility. AS2 is commonly used for side windows and rear glass, where different light transmission limits are permitted. AS3 generally indicates darker glazing often associated with privacy glass and is not appropriate for a front windshield in normal passenger vehicles, because it transmits less light. While the stamp does not tell you everything about the glass (for example, whether it is acoustic or solar), it quickly confirms that the glazing belongs in the location where it is installed. If you ever notice an unusual rating on a windshield—especially a rating not consistent with a front windshield—treat it as a red flag and have it checked. At Bang AutoGlass, we verify the AS rating during part confirmation so the replacement glass meets the correct glazing classification for the application, preserves visibility, and keeps the vehicle compliant with safety standards.
Windshield Date Codes: How to Tell the Build Month and Year
Many windshields include a date code that indicates when the glass itself was manufactured, which can help you understand whether the glass is likely original to the vehicle or a later replacement. There is no single universal "one format" that every manufacturer uses, but a very common system combines a single digit for the year with a row of dots (or sometimes small marks) that represent the month. In that common format, the digit corresponds to the last number of the year (for example, "4" could be 2014 or 2024), and the number and placement of dots are used to narrow down the month, sometimes with dots on one side meaning the first half of the year and dots on the other side meaning the second half. Because vehicle model years and registration dates provide context, you can usually tell which decade the code is referring to. The key is to treat the date code as a clue, not the only proof—especially on older vehicles or in cases where the stamp is partially worn. If you are trying to match glass for an appearance restoration, date codes can be very useful. For everyday replacement, Bang AutoGlass focuses on the VIN, part number, and feature symbols, and we use the date code mainly as supporting information to confirm what is currently installed.
Many date codes use a year digit plus dots or marks for the month, helping you estimate when the windshield glass was manufactured.
Because date-code formats vary by manufacturer, use the vehicle model year and other stamp details to interpret the decade correctly.
Date codes are best used as supporting evidence for originality or restoration, while VIN, part number, and feature icons should drive replacement selection.
Other Symbols You May See: HUD, Acoustic, Solar, Heated, Rain Sensor
Beyond DOT and AS ratings, many windshields carry feature symbols that matter for comfort and safety. A HUD (head-up display) marking may indicate a special laminate or "wedge" layer engineered to prevent double images when the projection reflects off the glass. Acoustic windshields often use an additional sound-damping interlayer; they are great for cabin quiet, but they should be matched correctly so the vehicle's noise performance stays consistent. Solar or UV markings can signal a coating that reduces heat and glare—helpful in bright climates and for protecting interiors. Heated windshield indicators may refer to a full heating element, a heated wiper park area, or embedded antenna elements; these options change both the wiring interface and what you see in the glass. You may also see icons related to a rain/light sensor, which usually means the glass includes a dedicated sensor pad or mounting location that must line up precisely with the sensor housing. None of these features are "nice-to-have details" when it is time to replace the glass; they are part of how the vehicle was built. If a replacement windshield is missing a HUD wedge, for example, the HUD can appear blurry or duplicated. At Bang AutoGlass, we use these symbols—along with VIN verification—to confirm you receive the right glass the first time, with all the features your vehicle is designed to use.
How to Use Markings to Order the Correct Replacement Glass
If you need replacement glass, the fastest way to avoid reorders is to treat the windshield markings as a starting point for a complete match. First, take a clear photo of the bug and any feature icons, plus a wide photo of the full windshield so a shop can see the tint band, camera window, and mirror area. Next, provide the VIN, because VIN-based catalogs link your exact trim level and option content to the correct glass part number. The markings help confirm what is installed today—brand, glazing rating, and feature clues—but they do not always identify every variation, especially on newer vehicles with multiple camera brackets or HUD configurations. A professional shop will cross-check the stamp with the required options (ADAS, rain sensor, heated elements, acoustic laminate) and inspect the mounting hardware to ensure the new glass will accept the existing brackets and trim without gaps. This is also the moment to plan for ADAS calibration: if your windshield has a camera module, ordering the correct glass and scheduling calibration should happen together, not as an afterthought. Bang AutoGlass uses a "verify, then order" process—VIN lookup plus stamp confirmation—so your replacement glass fits correctly, seals quietly, and supports all safety systems as intended.
Services
How to Read Windshield Markings: DOT Codes, AS Ratings, and Date Stamps
Where to Find the Windshield “Bug” (Stamp) and What It Identifies
Most windshields have a small cluster of markings etched into the glass called the "bug" or stamp. You will usually find it low on the driver or passenger side, near the corner, where it's visible but does not distract from the road. That stamp is more than branding—it is the windshield's ID card. It typically includes the glass maker's logo, a "DOT" code that identifies the prime glazing manufacturer, and a safety rating (such as AS1) that indicates the glazing classification used on public roads. Many stamps also include additional codes for part family, glass type (laminated vs tempered), and feature symbols such as acoustic laminate or solar coating. In the United States, the DOT marking is part of the required certification markings for automotive glazing, which is why you will see it on both original and replacement glass. Knowing where to look helps you make smarter decisions: you can compare markings on both sides of a vehicle, confirm whether a windshield has been replaced before, and provide accurate information when ordering glass or filing an insurance claim. At Bang AutoGlass, we often ask customers to snap a clear photo of the bug—because a single picture can confirm the right glass options and prevent delays caused by ordering the wrong configuration.
DOT Code Explained: Manufacturer ID and Compliance Basics
The DOT code on your windshield is often misunderstood. "DOT" does not mean the glass was made by the Department of Transportation; it means the glazing manufacturer is certifying that the glass meets U.S. glazing requirements and is marked with a manufacturer code that NHTSA assigns. Under FMVSS 205, the prime glazing manufacturer adds the "DOT" symbol plus its unique code mark to the required stamp, which makes the source of the glass traceable if there is ever a safety question. In practice, the DOT number helps identify who produced the glass and, in some cases, where it was made, but it is not a guarantee of being "OEM" or a direct quality ranking. Two windshields can both be compliant and still differ in features like acoustic interlayers, coatings, or bracket designs. That is why we treat the DOT code as one piece of a larger identification process. If you are curious, the manufacturer code can often be cross-referenced through public databases and manufacturer listings, and it can help confirm whether a windshield has been replaced with a different brand than factory. For ordering replacement glass, Bang AutoGlass uses the DOT stamp as a verification tool—paired with VIN-based part lookup—so the glass you receive matches the right fit, options, and certification markings.
A windshield DOT code is a certification marking under U.S. glazing rules that identifies the prime glazing manufacturer through a unique NHTSA-assigned number.
DOT numbers help trace who made the glass, but they do not guarantee OEM quality, so options and fitment still need to be verified.
Pairing a clear photo of the bug with VIN-based lookup prevents ordering the wrong windshield when multiple bracket and feature variations exist.
AS1 vs AS2 vs AS3: What the Safety Rating Means
The "AS" rating in the windshield bug refers to the safety glazing classification defined in the ANSI/SAE Z26.1 glazing standard that is referenced by U.S. law in FMVSS 205. Think of it as the glass's approved use category, tied to testing requirements and—importantly—light transmission. AS1 is the designation you will typically see on front windshields because it allows the high visible light transmission needed for safe forward visibility. AS2 is commonly used for side windows and rear glass, where different light transmission limits are permitted. AS3 generally indicates darker glazing often associated with privacy glass and is not appropriate for a front windshield in normal passenger vehicles, because it transmits less light. While the stamp does not tell you everything about the glass (for example, whether it is acoustic or solar), it quickly confirms that the glazing belongs in the location where it is installed. If you ever notice an unusual rating on a windshield—especially a rating not consistent with a front windshield—treat it as a red flag and have it checked. At Bang AutoGlass, we verify the AS rating during part confirmation so the replacement glass meets the correct glazing classification for the application, preserves visibility, and keeps the vehicle compliant with safety standards.
Windshield Date Codes: How to Tell the Build Month and Year
Many windshields include a date code that indicates when the glass itself was manufactured, which can help you understand whether the glass is likely original to the vehicle or a later replacement. There is no single universal "one format" that every manufacturer uses, but a very common system combines a single digit for the year with a row of dots (or sometimes small marks) that represent the month. In that common format, the digit corresponds to the last number of the year (for example, "4" could be 2014 or 2024), and the number and placement of dots are used to narrow down the month, sometimes with dots on one side meaning the first half of the year and dots on the other side meaning the second half. Because vehicle model years and registration dates provide context, you can usually tell which decade the code is referring to. The key is to treat the date code as a clue, not the only proof—especially on older vehicles or in cases where the stamp is partially worn. If you are trying to match glass for an appearance restoration, date codes can be very useful. For everyday replacement, Bang AutoGlass focuses on the VIN, part number, and feature symbols, and we use the date code mainly as supporting information to confirm what is currently installed.
Many date codes use a year digit plus dots or marks for the month, helping you estimate when the windshield glass was manufactured.
Because date-code formats vary by manufacturer, use the vehicle model year and other stamp details to interpret the decade correctly.
Date codes are best used as supporting evidence for originality or restoration, while VIN, part number, and feature icons should drive replacement selection.
Other Symbols You May See: HUD, Acoustic, Solar, Heated, Rain Sensor
Beyond DOT and AS ratings, many windshields carry feature symbols that matter for comfort and safety. A HUD (head-up display) marking may indicate a special laminate or "wedge" layer engineered to prevent double images when the projection reflects off the glass. Acoustic windshields often use an additional sound-damping interlayer; they are great for cabin quiet, but they should be matched correctly so the vehicle's noise performance stays consistent. Solar or UV markings can signal a coating that reduces heat and glare—helpful in bright climates and for protecting interiors. Heated windshield indicators may refer to a full heating element, a heated wiper park area, or embedded antenna elements; these options change both the wiring interface and what you see in the glass. You may also see icons related to a rain/light sensor, which usually means the glass includes a dedicated sensor pad or mounting location that must line up precisely with the sensor housing. None of these features are "nice-to-have details" when it is time to replace the glass; they are part of how the vehicle was built. If a replacement windshield is missing a HUD wedge, for example, the HUD can appear blurry or duplicated. At Bang AutoGlass, we use these symbols—along with VIN verification—to confirm you receive the right glass the first time, with all the features your vehicle is designed to use.
How to Use Markings to Order the Correct Replacement Glass
If you need replacement glass, the fastest way to avoid reorders is to treat the windshield markings as a starting point for a complete match. First, take a clear photo of the bug and any feature icons, plus a wide photo of the full windshield so a shop can see the tint band, camera window, and mirror area. Next, provide the VIN, because VIN-based catalogs link your exact trim level and option content to the correct glass part number. The markings help confirm what is installed today—brand, glazing rating, and feature clues—but they do not always identify every variation, especially on newer vehicles with multiple camera brackets or HUD configurations. A professional shop will cross-check the stamp with the required options (ADAS, rain sensor, heated elements, acoustic laminate) and inspect the mounting hardware to ensure the new glass will accept the existing brackets and trim without gaps. This is also the moment to plan for ADAS calibration: if your windshield has a camera module, ordering the correct glass and scheduling calibration should happen together, not as an afterthought. Bang AutoGlass uses a "verify, then order" process—VIN lookup plus stamp confirmation—so your replacement glass fits correctly, seals quietly, and supports all safety systems as intended.
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