A car windshield is made up of two pieces of glass that are separated by a layer of “PVB” (polyvinyl butyrate) that essentially ‘glues’ the two pieces together. This has several benefits, the most important being that in the event of a crash, it is much more difficult for objects outside a car to get in (or passengers to be ejected from the car), and the windshield is unlikely to break into lots of small pieces. This layer can also help block out harmful UV rays, can add some tinting, and can help reduce the amount of sound that comes through the windshield.

Read this page to learn learn more about how the Windshield is Made. And this page for an in-depth look at the rear windshield, how they are made and tips for repair.

Repair or Replace?

One of the first questions that comes up after a windshield is damaged is whether to repair it or replace it. Originally, damaged windshields had to be replaced. But that was very expensive, so windshield repair became common. In fact, many insurance companies will give you the option of repairing a windshield for free, instead of replacing it (in which case you might have a deductible to pay). Commonly, it is said that if a crack is smaller than 6″ long (or smaller than the size of a dollar bill), it can be repaired (and that chips/dings fitting under a credit card can be repaired). There is one company, UltraBond, that has a product that can repair cracks up to 24″ long.

Repairing is often desirable because it keeps the original factory installation of the windshield. Repairing also prevents the old windshield from being thrown out, helping the environment.

Read about a few things to consider when making decision whether to repair or replace a windshield.


Repairing typically costs about $50 for the first chip, plus about $10-$15 per additional chip. Cracks can be more expensive, depending on the length, up to about $100-$150. Replacing a windshield is significantly more expensive; the average price commonly being reported as $350 (but can be well over $1,000 if an OEM windshield is used). Which factors does the cost of replacing a windshield depend on? So, how much does it cost to replace a windshield?

Windshield Markings

Windshields (and other auto glass parts) have a marking that has information about the piece of glass and who manufactured it. Since we couldn’t find any good reference out there, we started our own! Feel free to check out our Windshield Markings Reference.

DOT Codes

All car windshields are required to have a DOT (Department of Transportation) code on them. Don’t worry about hunting all over the Internet; we’ve got a list of the codes right here.

Windshield Standards

Automobiles sold in the United States are covered by a series of safety standards called Federal Motor Vehicle Safety Standards (FMVSS). The ones related to windshields are FMVSS #205 (“Glazing Materials”) and FMVSS #212 (“Windshield Mounting”). You can find the standards on this site, both FMVSS205 and FMVSS212.


Normally, cracks in windshields are covered under the Comprehensive section of your car insurance policy. That section is usually optional, so there is a chance that you may not have any coverage. If you do have coverage, you probably have a deductible (typically $500). However, some states require no deductible (in which case you pay nothing), and others have lower deductibles (such as Massachusetts, which has a maximum $100 deductible, so the most you could pay is $100). Read more about Comprehensive Coverage, Zero-Deductible States, claims and Claim Procedures.

Driveaway Time

When a windshield is replaced, 1-hour driveaway times are common (meaning that after an hour, you can drive the car, and the windshield is guaranteed to stay in place). However, it can take 8-24 hours for the adhesive to fully dry. This means that in some types of collisions (rollovers or head-on collisions), the windshield could pop off, causing the roof to crush more easily, or airbags not to function properly (as they use the windshield for support).

Cracks, chips and scratches

Typically, cracks and chips occur when a rock or other road debris gets kicked up by a car in front of you, and hits your windshield. Cracks are also often the result of chips which were left unrepaired and grew into a larger problem. Glass scratches are often mistaken for cracks; the difference is that scratches do not go all the way through the glass. See description of different windshield chip and crack types on this page.

OEM vs. Aftermarket (ARG; Auto Replacement Glass)

OEM (Original Equipment Manufacturer) windshields are created differently than aftermarket ones (aftermarket parts are ones that are sold to replace the original parts of a vehicle). An article named “The Truth About OEM Phoenix Auto Glass Parts” says that “OEM auto glass standards require 100 percent windshield retention in frontal barrier crash tests, while DOT only requires 80 percent!” and that “Some aftermarket parts do not match the tolerance, thickness, and shape of OEM auto glass parts; therefore, they can have a higher rate of leakage, wind noise, imperfect fit, solar performance, and optical distortion”. Note that glass “from an OEM manufacturer” is not OEM glass, it’s just glass from the same company that made the original part (which may have completely different specs). ARG windshields have higher levels of stress, since manufacturers limit the stress allowable in the OEM windshields they contract for (source). Read about windshield Manufacturers: OEM, Dealer, and aftermarket.

Interestingly, many state laws allow the use of aftermarket parts, but define them as being either sheet metal or plastic. That implies that the laws do not apply to windshields (despite the term aftermarket applying to non-OEM windshields in standard usage), making interpretation of the laws more difficult.

So, Windshield Replacement: OEM or Aftermarket – or something else?

State Laws

For state-by-state information about what insurance covers, whether insurance can use aftermarket parts, and more, check out our State-by-State Page.

Misc. Facts

Auto glass technicians make an average of about US$30,000/year.

13-14 million windshields are replaced each year.

There are no Federal or State regulations covering replacement windshields! (source).

You can help keep a crack from getting debris in it (which could prevent it from being repairable) by covering it with clear packing tape (but don’t use other types of tape, which could make repair more difficult).

OEM windshields cost car manufacturers less than that of aftermarket windshields, due to the high volume that the car manufacturers order (source)

Part Number Lookup

If you have a “NAGS” part number, such as “FW02628 GBYNMF”, you can look it up here.

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Part Number Search

If you want to look up a part number for a recent model year car, you can do so here. Note that the database is not well populated, so you may or may not find what you are looking for (if anyone has access to the full database, please let us know!).

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Comprehensive Glossary

Not sure what a term means? Look it up in our glossary of car windshield terms.