Windshield Damage Types: A Complete Identification Guide
The short answer
- Damage with a visible impact point (a pit) is an impact break. Damage with no pit is a stress crack, and stress cracks are almost never repairable.
- Bullseyes and half moons are the easiest breaks to repair well. Star breaks and combination breaks are repairable but more likely to leave a visible blemish.
- Location beats size: any break within about two inches of the glass edge, or in the driver's direct sight line, pushes toward replacement even when it is small.
- Contamination and time matter. A clean break repaired within days fills better than the same break left open for a month of rain and car washes.
- Damage that reaches the inner glass layer, or shows a milky moisture stain between layers, cannot be repaired from the outside.
Every windshield break falls into one of about a dozen recognized shapes, and the shape tells you most of what you need to know: whether resin can fill it, how fast it is likely to grow, and whether a shop will quote a repair or a replacement. This guide describes each type, what causes it, and how it typically behaves. If you want a faster answer, work through the visual damage identifier and then the repair or replace tool.
The anatomy of a break
A windshield is laminated safety glass: two plies of annealed glass bonded to a PVB interlayer. Almost all visible damage lives in the outer ply only. That is why repair works at all, because resin can be drawn into a void that is capped underneath by intact plastic.
Three features let you name any break:
- The pit. The crater on the outer surface where something struck, where glass is actually missing. No pit anywhere means it is not an impact break.
- The cone. Beneath the pit, the impact drives a conical fracture down into the outer ply. Its shape decides whether you get a bullseye, a half moon, or a star.
- The legs. Radial cracks running outward from the impact. Long, fine legs are the hardest part of any repair to fill and the part most likely to run later.
Learn those three and the naming falls out on its own.
Damage type comparison table
Repairability reflects common practice under the industry repair standard (ROLAGS) and the limits most shops and insurers apply. Spread risk is how likely the damage grows within weeks if left alone.
| Type | What it looks like | Typical cause | Typical repairability | Spread risk |
|---|---|---|---|---|
| Pit (surface chip) | A small crater or nick in the outer surface, no legs, no dark halo, often under 3 mm. Catches a fingernail. | Small stone or grit at speed, or an ice scraper corner. | Not a structural repair. Filled and polished cosmetically (pit polish) or left alone. | Very low alone, but a pit is the weak point a thermal swing turns into a crack. |
| Bullseye | A clean dark circle or ring around the pit, like a target. | A rounded stone striking near perpendicular. | Best case. Commonly repaired up to about 1 inch across, often nearly invisible after. | Low to moderate. No leg tip to concentrate stress. |
| Half moon (partial bullseye) | A crescent or D shape rather than a full circle. | A stone striking at an angle instead of head on. | Very repairable, same limits as a bullseye. Resin flows well into the crescent. | Low to moderate. Blunt ends do not run easily. |
| Star break | A pit with fine radial legs fanning out, like a spider. | A hard, angular stone, also common from frozen road grit. | Repairable to roughly 1.5 inches overall including legs. Expect a faint residual mark. | High. Leg tips concentrate stress, so heat cycles and flex extend them. |
| Combination break | A bullseye or half moon core with star legs coming off it. The most common real world break. | Medium stone at highway speed. | Usually repairable under about 1.5 inches total, if no leg nears the edge. | High. It inherits the star's running legs. |
| Surface pit cluster | Many tiny pits over a broad area, seen as haze or starburst glare against headlights. | Cumulative sandblasting from highway miles and winter grit. | Not repairable. Polishing removes glass and adds distortion, so replacement is the honest fix. | No spread, but it worsens steadily and is a night driving hazard. |
| Floater crack | A single line crack starting and ending inside the glass, touching no edge. | An impact whose legs kept running, or an unrepaired star that walked. | Sometimes repairable with a long crack system, commonly up to about 12 to 14 inches. | Moderate to high. Both tips are live and can extend. |
| Edge crack | A crack reaching or starting within about two inches of the perimeter, often curving. | Impact near the edge, body flex, or installation stress at the pinch weld. | Generally not repairable. Shops and insurers treat edge damage as replacement. | Very high. The bonded perimeter carries load, so these run quickly. |
| Stress crack (no impact point) | A crack with no pit anywhere, usually starting at the edge and running inward. | Thermal shock, chassis twist, pinch weld or moulding pressure, or a glass defect. | Almost never repairable. No cavity to inject and no pit to seal. | Very high. The load that caused it is still present. |
| Chip in the driver's view zone | Any break in the area swept directly in front of the driver at eye height, below the AS-1 line. | Same causes as any impact break. Location is what defines it. | Possible but discouraged by the repair standard, since cured resin can leave slight distortion. | As for the underlying type, but the consequences of a poor repair are higher. |
| Laminate delamination and moisture stain | A cloudy, milky or brownish halo spreading from old damage or the edge, sometimes with a rainbow sheen. | Water wicking into the PVB interlayer through an unsealed break or a failed perimeter seal. | Not repairable. Resin cannot displace water and the glass to PVB bond is already lost. | Slow, permanent and progressive. It never reverses. |
| Inner layer break | Damage you can feel with a fingernail from inside the car, or cracks clearly on the cabin side. | An object striking from inside, a heavy outside impact carrying through, or severe body stress. | Not repairable by chip repair, which treats the outer ply only. Replacement. | Varies, but a break through both plies is a structural concern. |
Impact breaks in detail
Bullseyes and half moons repair well because the cone is a broad, open cavity. Resin fills it under a normal vacuum and pressure cycle, and once UV cured its refractive index is close enough to glass that the ring largely disappears, often leaving only the pit mark visible.
Star breaks are the opposite problem. The legs are hairline voids that taper to nothing, and air trapped at a leg tip leaves the silvery line you still see after a mediocre repair. Clearing it takes repeated vacuum cycles and low viscosity resin, which takes time, so an unhurried repair beats a fast one. See what a repaired chip looks like for realistic expectations.
Combination breaks are the two together, and the most frequent thing a shop sees. Judge them by their widest dimension including every leg, not by the round core.
Cracks in detail
A crack is a fracture that has already chosen a direction. Once it is moving, the question shifts from resin chemistry to stress. Floater cracks are the only crack type routinely repaired, and even then the result is a stabilized line you can still see, not an invisible fix.
Edge cracks behave differently because the outer band of the glass is bonded to the body with urethane adhesive and carries structural load. Stress concentrates there, so a break that would be trivial in the middle of the glass becomes a replacement at the perimeter. Edge cracks covers how to measure that two inch band correctly.
Stress cracks matter for a different reason: cause. A crack with no impact point may point to a glass defect or an installation fault, both of which can be warranty items rather than a bill you pay. Work through stress cracks versus impact cracks before you accept a quote.
Cases where the shape does not decide
Three situations override the normal size rules.
Driver's view. A repair in your direct sight line can leave a small optical artifact permanently in the worst possible place. Ask the shop what they expect the result to look like, and consider replacement if you drive at night often. The AS-1 line and driver view page explains the zone rules.
Moisture in the laminate. A milky stain means water reached the PVB. Once the interlayer has absorbed water and lost adhesion, no external process restores it. It is common on breaks left open through a wet season and on older glass with a failing perimeter seal.
Inner ply involvement. Run a fingernail over the inside face. If you catch an edge, the damage went through. Standard chip repair addresses the outer ply only, so this is a replacement conversation, which usually brings in ADAS calibration on any vehicle with a forward facing camera.
Size and location thresholds
These are the working limits most shops apply. They are typical practice ranges, not a legal standard, and an individual shop or insurer may be stricter.
| Measurement | Usual repair limit | Why the limit exists |
|---|---|---|
| Bullseye or half moon diameter | About 1 inch (roughly a quarter) | Larger cavities shrink more as resin cures, leaving visible rings. |
| Star or combination diameter, legs included | About 1.5 inches | Long legs are hard to evacuate and prone to running during the pressure cycle. |
| Crack length | About 6 inches for standard tooling, up to 12 to 14 inches with a long crack system | Longer cracks need multiple injection points and rarely stay invisible. |
| Distance from glass edge | At least 2 inches | The bonded perimeter is a high stress zone where an injector cannot hold vacuum. |
| Number of breaks on the glass | One to three is normal for repair, four or more is a replacement | Multiple resin sites in the wiper path add cumulative distortion. |
A four step identification routine
- Find the pit. Feel with a fingernail from outside. A catch means an impact break. No catch anywhere along a crack means a stress crack.
- Name the core. Round ring is a bullseye, crescent is a half moon, radiating lines are a star, both together is a combination.
- Measure the widest span. Include every leg tip. Compare to a quarter and a dollar bill (a bill is about 6.1 inches long) rather than guessing.
- Measure to the edge. From the damage to the visible glass edge under the moulding, not to the black frit border, which extends inward and will fool you.
With those four answers you have a defensible decision, and chip repair cost tells you what each path should run. If the damage is fresh, act quickly: the argument for speed is in how soon to repair a chip, and the mechanics of growth are in will a crack spread.
Frequently asked questions
What is the difference between a chip and a crack?
A chip is damage centered on an impact point where glass has been removed or fractured locally, usually under an inch across. A crack is a single line fracture that travels. Chips are usually repairable. Cracks are repairable only in limited lengths and locations.
Can a star break be repaired?
Usually yes, if the overall diameter including the legs stays under roughly 1.5 inches, it sits away from the edge, and the legs have not started walking. Star breaks trap air in narrow legs, so expect a faint visible mark after a good repair.
Why does my crack have no chip at the end?
That is a stress crack. It comes from thermal shock, body flex, or installation pressure rather than a stone strike, and it typically starts at the glass edge. Stress cracks have no impact point to inject resin into, so replacement is the normal outcome.
Is a small chip in front of the driver repairable?
Technically yes, but the industry repair standard discourages it because cured resin can leave slight distortion in the primary viewing area. Many shops will repair it only after telling you a faint mark may remain, and some decline and quote a replacement.