What is a NAGS number for auto glass?
Reviewed by the Skyview Auto Glass technical team — NWRD-, ASE- and DINITROL-trained technicians · Updated November 2026
Quick answer
A NAGS number is the part number listed in the National Auto Glass Specifications catalogue, the industry’s standard reference for identifying auto glass. Shops use it to order the right pane when a vehicle takes several versions. It is a useful shorthand, but the VIN remains the reliable way to match a replacement, because it resolves the exact specification.
What is a NAGS part number?
NAGS stands for National Auto Glass Specifications, a catalogue that assigns a standard number to every auto glass part sold in the market. The catalogue exists because the same vehicle can be built with several different windshields, and a plain description like a windshield for a given model is not enough to pick the right one. The NAGS number pins the pane down to a specific part.
Shops, suppliers, and insurers all use these numbers as a common language. A quote that lists a NAGS number tells everyone in the transaction exactly which pane is meant, which matters when one version of a windshield carries a camera bracket and another does not, or one is acoustic and the other is standard.
The number is a starting point, not the final word. Two panes can share a catalogue entry while small differences in features or fittings separate them, and a catalogue cannot see how an individual vehicle was optioned. That is why a careful shop resolves the part from the VIN, which identifies the vehicle as built, and uses the catalogue number to order once the specification is settled.
How a glass part number is used
A part number works alongside the other identifiers on and around the glass.
| Identifier | Where it lives | What it tells you |
|---|---|---|
| NAGS number | In the supplier catalogue and on the invoice | The standard catalogue identity of the pane being ordered |
| Maker’s part number | Etched in the bug on the glass | The manufacturer’s own designation for that pane |
| DOT code | Etched in the bug | Which manufacturer made the glass |
| VIN | On the dashboard and door jamb | How the vehicle was actually built, which resolves the exact pane |
The etched markings are described in our guide on what the markings on a windshield mean.
The VIN is the reliable way to pick the part
At Skyview the VIN is matched to the exact part number before anything is ordered, so the replacement pane carries the same features and sensors as the one it replaces. See our auto glass part numbers guide for how that lookup works.
More questions about NAGS numbers
How do I find my windshield part number?
The maker’s number is etched into the bug in a corner of the glass, usually the passenger side. The catalogue number is a shop-side reference resolved from your vehicle, which is why glass shops ask for the VIN rather than for a number you read off the pane.
What do the letters in a glass part number mean?
There is no single universal code. Prefixes and suffixes vary by maker and by catalogue, and they mark things like the glass position on the vehicle, the version of the pane, and features such as a shade band or a sensor area. The markings only reliably decode with the maker’s or the catalogue’s own key.
Do insurers use NAGS numbers?
Yes, glass claims are commonly priced against catalogue numbers because they give the claim a standard part identity. The shop still verifies the pane against the VIN before ordering, so the feature set on the vehicle is what drives the final part choice.
Related guides
More in Glass types and features
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