Windshield Crack Types: How to Spot Each One and Fix It

Most windshield damage falls into a handful of types: bullseye, half-moon, star break, combination break, surface pit, long crack, edge crack, floater crack and stress crack. Each one looks different, and the type, size and location tell you whether a quick resin repair will do or the glass has to be replaced. This guide shows you how to recognize each type, what makes a crack serious, and what heat, cold and daily driving do to damage you already have.

TL;DR

• Impact damage (bullseye, half-moon, star, combination, pit) starts at a point where something hit the glass. Stress cracks have no impact point and usually start at an edge.
• Industry repair standards allow resin repair of many chips up to about 1 to 3 inches and cracks up to 14 inches, but never a stress crack or damage that goes through both glass layers.
• A simple field test from AAA: a chip about the size of a quarter or a crack a dollar bill can cover is generally repairable. Anything longer or near the edge usually means replacement.
• Temperature swings, vibration and car washes can make existing damage spread, so fix chips early.
• In Walnut Creek, Oakley and the East Bay, we come to your home or workplace for repair or replacement.

Table of Contents

• The main windshield crack types at a glance
• Impact damage: chips that start at a hit
• Cracks: lines that travel
• Which windshield cracks can be repaired and which cannot
• Why the windshield matters structurally
• Windshield cracks and heat
• Windshield cracks in cold weather
• Can a crack spread while you drive?
• How to tell if a crack is serious
• What to do right after you notice damage
• Our perspective: fix the small thing while it is small
• Get it fixed where you park
• FAQ
• Sources

The main windshield crack types at a glance

Shops use slightly different names, but the vocabulary below follows the definitions in the ROLAGS repair standard definitions, the industry’s reference for windshield repair terms. The table puts the types side by side.

Below is what each one means in practice.

Impact damage: chips that start at a hit

Impact damage comes from a rock, gravel or debris striking the outer layer of glass. Windshields are laminated: a layer of plastic between two sheets of glass. That is why they crack instead of shattering, according to the Raleigh News & Observer’s reporting on car glass. It is also why a chip can be filled and stabilized rather than the whole windshield being thrown away.

Surface pit

A pit is a small nick in the glass that comes from normal wear and does not reach the plastic interlayer, per the ROLAGS definitions. You feel it with a fingernail but see no cracks around it. Pits are the one type you can often ignore for a while, though a pit in your direct line of sight can cause glare at night.

Bullseye

A bullseye is a separated cone in the outer glass that shows as a dark circle with the impact point in the middle. It is usually the cleanest type to repair because the damage is contained. Under the ANSI ROLAGS 002-2022 standard, a bullseye no larger than 1 inch in diameter is repairable on laminated glass.

Half-moon

A half-moon is a partial bullseye: a semicircle of broken glass around the impact point. The same 1 inch limit applies. Half-moons often sprout short cracks from the edge of the arc if they sit untreated.

Star break

A star break has a series of legs radiating from the impact point. The legs are what make it risky: each one is a path for a crack to travel. The standard allows repair of star breaks up to 3 inches in diameter, but it says not to repair damage with three or more long cracks coming from a single impact point.

Combination break

A combination break mixes characteristics, such as a star inside a bullseye. It is the most common type, since real rocks do not hit in textbook shapes. The standard allows repair when the body of the damage is up to 2 inches across.

Cracks: lines that travel

A crack differs from a chip because the damage is a line rather than a spot. The length matters first.

• Short crack: 6 inches (150 mm) or less.
• Long crack: more than 6 inches. The ROLAGS standard still allows repair of a crack up to 14 inches (350 mm) when other conditions are met, which surprises many drivers.

AAA gives a simpler rule of thumb. In its guidance on fixing versus replacing a windshield, repair is generally a good option if a chip is an inch or less across, about the width of a quarter, or if a dollar bill can fully cover a crack. If the crack is larger than a dollar bill or close to the edge, structural integrity may be compromised and replacement is likely needed. For a deeper size breakdown, see our windshield crack size chart.

Edge crack

An edge crack runs to an edge of the windshield. The edge is where the glass is bonded to the car body and where it is under the most tension, so these cracks spread faster than cracks in the middle. The standard says not to repair edge cracks that intersect more than one edge, and in practice many edge cracks end in replacement.

Floater crack

A floater crack starts somewhere in the middle of the glass and does not extend to an edge. These are safer to repair than edge cracks, provided the length is within limits and the crack is not in your direct line of sight. Left alone, a floater can travel to the edge and become an edge crack.

Stress crack

A stress crack extends from an edge and has no impact point, per the ROLAGS definitions. It typically appears as a single line, often curved, with no chip at the start. The standard lists stress cracks among damage that should not be repaired. We cover causes and fixes in detail in our guide to the stress crack in your windshield.

One point worth knowing: what looks like a spontaneous stress crack can be an old impact in disguise. A Nissan technical service bulletin published by NHTSA explains that a lead from a star-cracked impact point can run to the glass edge and look like a stress crack that began at the edge. A tiny, forgotten chip may be the real starting point.

Which windshield cracks can be repaired and which cannot

The repair standard is the best yardstick, because it is written by the industry’s repair division. The ROLAGS 002-2022 standard sets these maximums for laminated glass:

• Bullseye: up to 1 inch
• Half-moon: up to 1 inch
• Star break: up to 3 inches
• Combination break: body up to 2 inches
• Crack: up to 14 inches
• Surface pit: at least 1/8 inch in diameter

The same standard says damage should not be repaired when:

1. It penetrates both layers of the laminated glass.
2. Three or more long cracks come from one impact point.
3. It is on the inside layer of glass.
4. Visible impurities cannot be cleaned out.
5. The plastic interlayer is damaged or discolored.
6. A pit is larger than 3/8 inch.
7. Edge cracks intersect more than one edge.
8. The damage is a stress crack.

The driver’s line of sight

Location changes the rules. The National Windshield Repair Division’s guidance on right repairs says that in the driver’s primary viewing area, repair is not recommended if the damage is larger than 1 inch, if the finished pit will be greater than 3/16 inch, or if it falls within 4 inches of another repair. Resin repair can leave a slight blemish, and directly in front of your eyes that blemish can be a distraction.

AAA’s article on saving money by repairing a windshield adds that damage under three inches long or two inches across, outside the driver’s direct line of sight, can often be repaired.

Our repair vs. replacement guide walks through the same decision with photos and examples.

Why the windshield matters structurally

The windshield is not just a window. AAA notes that it plays a structural role, and that even a small chip compromises the integrity of the glass, raising the chance of it breaking in a collision. That is the reason a chip is worth fixing even if it does not bother your view.

Windshield cracks and heat

Heat is the most common reason a small crack grows. The glass expands unevenly when part of it is hot, for example when the sun hits one side or the defroster blasts hot air at a cold pane. A chip or edge flaw concentrates that stress.

The Raleigh News & Observer quotes an auto glass expert who says an unrepaired crack is virtually certain to spread in extreme heat or cold. Treat that as a strong warning rather than a precise forecast, but the direction is clear.

Practical habits that help:

• Park in shade or use a sunshade when you have a chip.
• Do not aim the defroster at full heat on a cold, cracked windshield. Warm the cabin gradually.
• Skip the car wash until the chip is repaired. The same article reports that taking a windshield to a car wash can cause the glass to react.

Windshield cracks in cold weather

Cold works the same way in reverse. Water that enters a chip can freeze and expand, and a sharp temperature drop adds stress. AAA warns that when extreme weather and rapid temperature changes are factored in, even minor cracks can worsen quickly, and that a neglected chip can take on water and fog the glass, hurting visibility.

In the East Bay, the swing is less about deep freezes and more about cool mornings followed by hot afternoons. That daily swing is enough to push an open chip. If you have damage and the forecast is changing, repair before the season, not after.

Can a crack spread while you drive?

Yes. The News & Observer reports that cracks can worsen even while you are driving. The NHTSA-published Nissan bulletin explains one path: fine sand, hard particles or dirty wiper rubber, especially on dry glass, can scratch the surface. A scratch can cause a small rupture in the outer glass, which can lead to a crack from thermal conditions, vibration or wind pressure.

So a few habits protect the glass between repairs:

• Never run the wipers dry over a chip or on dusty glass. Use washer fluid.
• Replace worn wiper blades so grit does not drag across the surface.
• Avoid slamming doors with the windows up when you have a long crack. The pressure pulse can push it.
• Keep more distance behind trucks, since gravel hits are the main source of new damage.

The same news article notes that vehicles with less slanted windshields, such as Jeeps and Toyota 4Runners, take more direct rock hits.

How to tell if a crack is serious

Use this quick check in a parked car, in good light:

1. Measure. A chip wider than a quarter or a crack longer than a dollar bill is past the easy-repair zone.
2. Locate. Is it within 2 inches of an edge, or in front of the driver? Both push toward replacement.
3. Count the legs. Three or more long cracks from one impact point is a no-repair situation under the industry standard.
4. Feel both sides. Run a fingernail over the inside. If you feel damage inside, it has gone through.
5. Look for growth. Mark the end of a crack with a dry-erase marker, if you can, and check again in a day.

A crack that grows, branches, or has no visible starting chip deserves a look from a technician soon. In California, the rules on cracked glass add another reason; our guide to the law on driving with a cracked windshield in California explains where the line is.

What to do right after you notice damage

1. Cover a fresh chip with clear tape to keep out dirt and moisture until it is repaired. Do not use glue or household resin.
2. Stay out of extreme temperature swings. No hot defroster, no car wash.
3. Call your insurance company or let your glass provider do it. AAA advises assessing the damage, then contacting your insurer to learn whether it is covered, whether you owe a deductible, and how to coordinate repair or replacement.
4. Book soon. AAA says acting at the first chip or crack lowers the chance of needing a more costly replacement.

Our perspective: fix the small thing while it is small

We see the same pattern across Walnut Creek, Oakley and the East Bay: a chip that would have been a 20-minute repair becomes a replacement because a hot afternoon or a pothole turned it into a long crack.

Our view is simple. Identify the type, decide quickly, and come to the driver. That is why we work at your home or workplace instead of asking you to give up half a day at a shop. A chip repair is our one published price, $125, and many customers pay little or nothing when insurance covers it.

When the damage is a stress crack, an edge crack or a long run across your line of sight, replacement is the right call, and we do it with OEM-equivalent glass backed by our lifetime warranty on materials and labor. Our technicians are certified for general auto glass work and for Tesla and ADAS procedures, so cars with a forward camera get their calibration handled as part of the job.

If you are not sure which type you have, send us a photo. We will tell you plainly whether it is a repair or a replacement.

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Get it fixed where you park

We repair chips and cracks and replace windshields at your home or office across Walnut Creek, Oakley and the surrounding East Bay. A chip and crack repair is $125, and we handle insurance paperwork at no cost. Replacement, side and rear glass, and ADAS camera calibration are quoted per vehicle on our services page.

If your damage is a small bullseye, half-moon or star, start with our windshield repair service in Walnut Creek or see how insurance can cover chip repair. If the crack is long or reaches the edge, our page on repair versus replacement shows what to expect, and if you cannot drive safely, we offer emergency windshield replacement in the East Bay. Our lifetime warranty applies to our work.

FAQ

What kind of windshield cracks cannot be repaired?

The industry standard says not to repair damage that goes through both glass layers, has three or more long cracks from one impact point, sits on the inside layer, or has a damaged or discolored interlayer. It also rules out edge cracks that cross more than one edge, pits larger than 3/8 inch, and stress cracks. Those cases need replacement.

What does a stress crack look like in a windshield?

It is usually a single line, often curved, that starts at the edge of the glass with no chip or impact point at its start. It typically appears after a temperature change or from pressure on the glass. Before assuming it is a true stress crack, check the edge for a tiny old chip, since a missed impact can look the same.

Will a windshield crack spread on its own?

Often, yes. Heat, cold, vibration and wind pressure all act on the weak spot, and AAA advises repairing chips of any size because even a tiny chip can grow. The longer it sits, the likelier it moves from repairable to replacement territory.

Can I drive with a cracked windshield?

Short-term driving to a repair is common, but a crack in your line of sight or one that is spreading is a safety problem, since the windshield supports the structure of the car in a collision. Rules vary by state, and our California guide explains the local law. If the damage is serious, we can come to you.

Sources

• Definitions, ROLAGS
• Repair of Laminated Auto Glass Standard, ANSI AGSC NWRD ROLAGS 002-2022
• The Right Repairs at the Right Time, National Windshield Repair Division
• Windshield Repairs: When to Fix vs. Replace, AAA
• How Repairing Your Windshield Can Save You Money, AAA Via
• Nissan technical service bulletin: Windshield Cracking, NHTSA
• Car glass cracking in extreme heat, The News & Observer

Recommended

• Windshield Crack Repair vs Replace — When Can You Repair It?
• Windshield Crack Size Chart: Repair or Replace?
• How to Prevent Windshield Damage — 8 Tips That Actually Work
• Windshield Repair vs Replacement: Which Do You Need?