Bullseye or Star Break: Telling Them Apart and Why It Matters
The short answer
- Name the break by its boundary: a bullseye is a closed round dark disc, a star break is a pit with fine legs running out of it, and most highway strikes are both at once.
- Star breaks and combinations are the urgent ones. Book within 2 to 3 days, because every leg tip is a live crack tip. A clean bullseye away from the edge can usually wait 1 to 2 weeks.
- Measure tip to tip including every leg, not the round core. Shops repair bullseyes to about 1 inch and stars to about 1.5 inches, and nothing within about 2 inches of the glass edge.
- Expect different results. A fresh bullseye often finishes close to invisible. A star break usually keeps faint silver lines where air stayed trapped at the tapered ends of the legs.
- Find legs by putting light across the glass at a shallow angle rather than looking through it. Hairline legs are invisible head on and flash silver under raking light.
Look at the boundary of the damage, not its size. A bullseye is a closed, round, dark disc sitting under the impact point, like a small coin trapped in the glass. A star break is a pit with fine lines radiating out of it, like a crack pattern in ice. That single difference decides how many days you can safely wait and how good the finished repair can look, because every leg on a star break is a live crack tip and a bullseye has none.
The one minute light test
Do these three checks in order, in daylight or with a flashlight, and you will have the answer before you call a shop.
- Get light raking across the glass. Stand so the sun or a streetlight comes across the windshield at a shallow angle rather than shining straight through it, then move your head slowly. Hairline legs are almost invisible when you look through the glass and flash bright silver when light skims along them. This is the check most people skip, and it is the one that finds legs.
- Backlight it from inside. Hold a phone flashlight inside the car about a foot from the damage, aimed along the surface rather than at it, and look from outside. A bullseye cone lights up as a solid bright disc with a smooth outline. Star legs light up as separate thin lines with dark glass between them.
- Read the shadow. In direct sun, hold a piece of white paper against the inside of the glass under the damage. A bullseye throws a round shadow with a clean rim. A star throws a spidery shadow with distinct arms. A combination throws a disc with arms coming off it.
A fingernail will not separate these two, because both have a pit and both catch. The fingernail test is for a different question: run it over the inside face of the glass, and if it catches there you are dealing with damage in the inner layer, which is a replacement conversation rather than a repair one.
Why the same stone makes two different shapes
When something strikes the outer glass ply, the impact drives a cone shaped fracture down from the contact point. What that cone does next is what you end up looking at.
A rounded object arriving close to perpendicular loads the glass over a small but blunt area. The cone separates cleanly all the way around and stops, and the ring you see is air sitting in the separation, which is why it looks dark or silver rather than clear. That is a bullseye.
An angular object, a steeper strike angle, a faster closing speed or colder glass concentrates the same energy into a smaller contact patch and into glass that is already carrying more tension. The cone cannot absorb it, so the fracture relieves the excess by running outward along radial lines. Those lines are the legs, and that is a star break. Cold winter glass and highway speeds are why star breaks are common in February on the interstate and bullseyes are common in a parking lot in July. The full mechanism of what happens after the legs exist is covered in how a crack actually grows.
Side by side identification
Work down the left column with your own glass in front of you. You need three or four rows to agree before you name it.
| What you check | Bullseye | Star break | Combination |
|---|---|---|---|
| Outline around the pit | Closed circle or crescent, smooth rim | No closed outline, only lines leaving the pit | A closed core with lines leaving it |
| Under raking light | Disc brightens as one shape | Individual legs flash silver one at a time | Disc plus flashing legs |
| Backlit from inside | Solid bright disc | Separate bright lines with clear glass between | Bright disc with lines running off it |
| Shadow on white paper | Round with a clean rim | Spidery arms, no rim | Round rim with arms |
| Widest measurement | Diameter of the disc | Tip of one leg to tip of the opposite leg | Tip to tip including every leg, not the core |
| Usual repair size limit | About 1 inch, roughly a quarter | About 1.5 inches including legs | About 1.5 inches including legs |
| How soon to book | 1 to 2 weeks if it is away from the edge | 2 to 3 days | 2 to 3 days |
| Realistic look after repair | Often close to invisible, pit mark may remain | Faint silver lines usually stay visible | Core clears well, legs usually stay faint |
If two rows disagree with each other, you almost certainly have a combination break, which is the most common pattern on a highway strike. The visual damage identifier walks the same decisions with pictures if you want a second opinion, and the full damage type guide covers the shapes this page does not, such as half moons, floaters and pits.
The combination break, and the measuring mistake it causes
A combination break is a bullseye or half moon core with star legs coming off it. It happens when a medium stone strikes hard enough to open a cone and then still has energy left to spend. It is not a separate species, it is both breaks at once, and it inherits the worse half of each: the cavity volume of a bullseye and the running legs of a star.
The mistake it produces is a measuring mistake. Drivers measure the round core, decide it is well under a quarter, and report a small bullseye. The shop measures tip to tip including the legs, gets 1.75 inches, and declines the repair on arrival. Measure the way a technician measures, described in measuring your damage, and measure the distance to the glass edge as well, because a single leg pointing at the perimeter can put an otherwise easy break into edge crack territory.
One leg changes the answer. A quarter inch bullseye with one 1 inch leg is not a bullseye for any decision that matters. It is urgent like a star, it prices like a star, and it will look like a star when it is done. Always name the break by its worst feature.
Why the difference changes your timeline
Stress concentrates at a sharp tip. A star leg ends in a fracture tip with an extremely small radius, so the tension the panel is already carrying is multiplied many times in the tiny volume of glass right at that tip. Add a cold morning, a pothole or a door slammed with the windows up, and that is where the glass gives first. A bullseye has no such tip anywhere on it. Its boundary is a blunt, closed curve, so the same panel stress is spread rather than amplified.
That is the whole reason the urgency differs, and it is why size is a poor guide. A quarter inch star break is a more urgent problem than a three quarter inch bullseye. Both are more urgent than either if they sit within about 2 inches of the bonded edge. If you want to put a risk band on your specific damage, work through the spread risk score, and if you are deciding how hard to push for an appointment this week, how soon to repair a chip has the timeline by damage type.
What each one looks like when it is finished
This is the part shops explain badly, and it is the source of most disappointment after a repair.
Repair works by pulling air out of the break under vacuum and pushing in a resin whose cured refractive index is close to that of glass. Where the resin fully replaces the air, the damage stops reflecting light and largely disappears. Where any air remains, you still see a bright line or a silver flash.
- A bullseye is one open cavity. It has a single volume with a smooth boundary, so it evacuates and wets out completely. A fresh, clean bullseye repaired within a few days often leaves nothing but a small mark at the pit itself.
- A star leg tapers to nothing. The last fraction of an inch of each leg is thinner than the resin can easily reach, and air trapped there is what you see later as a fine silver line. Repeated vacuum and pressure cycles and a low viscosity resin push the fill further out, which is why an unhurried repair beats a fast one.
- Contamination hurts stars far more. Water and road grime wick along a leg and sit in exactly the place resin needs to reach. A two week old bullseye repairs nearly as well as a fresh one. A two week old star break often does not.
Set expectations before the technician starts, not after. What a repaired chip looks like shows the honest range of results, and how chip repair works explains the vacuum and pressure cycles that decide which end of that range you land on. Neither break type costs more in most shops: chip repair typically runs $60 to $150 cash, with additional chips on the same glass often $10 to $40 each.
What it costs to call it wrong
| You called it | It was actually | What that costs you |
|---|---|---|
| A bullseye, on the phone | A star break | A short appointment slot booked for a break that needs several cycles. The technician either rushes it or reschedules you. |
| A small bullseye | A combination measured tip to tip | Repair declined at the door for exceeding size limits, and a wasted trip. |
| Not urgent | A star with a leg pointed at the edge | A crack across the glass within days, turning a $60 to $150 repair into a $300 to $900 or higher replacement. |
| Simple enough to do yourself | A star break with contaminated legs | Kit resin cures inside the legs and cannot be removed, so a professional repair can no longer reach them. |
| A star break | A crack with no pit anywhere | You chase a repair that was never available, when the real question is what caused a stress crack and whether it is a warranty matter. |
The last two rows are the expensive ones. The DIY trap is worth taking seriously, because it is irreversible: see the mistakes that ruin a repair before you open a kit on a star break.
The green light case. A closed round bullseye under about 1 inch, more than 2 inches from every glass edge, outside your direct sight line, less than a couple of weeks old and kept dry is the easiest repair in the trade. Book it, expect a near invisible result, and do not let anyone talk you into a replacement.
What to do with the answer
If you have a star or a combination, treat it as a this-week job and keep the glass out of thermal shock until the appointment. If you have a clean bullseye away from the edge, you have a little more room, but the contamination clock is still running and there is no advantage to waiting. Either way, cover the pit with a small square of clear tape and keep liquids out of it.
Two pages take you the rest of the way. Run the damage through the repair or replace tool to confirm you are still inside repair limits, and read can my windshield be repaired for the size, location and sight line rules a shop will apply when you arrive.
Frequently asked questions
Is a star break worse than a bullseye?
Yes, on both counts that matter. A star break has sharp fracture tips that concentrate stress, so it is far more likely to run into a full crack, and its legs taper too thin for resin to fill perfectly, so it usually stays faintly visible after repair. A bullseye has a blunt closed boundary and neither problem.
Can a star break be repaired?
Usually yes, if the overall span including every leg is under roughly 1.5 inches, no leg comes within about 2 inches of the glass edge, and the damage is not in your direct sight line. Book it quickly. Star legs collect moisture and grime fast, and contamination is what turns a good result into a cloudy one.
My chip has a ring and some lines. Which one is it?
That is a combination break, and you should treat it as a star for every decision. Use the star timeline of two to three days, measure it tip to tip across the legs rather than across the round core, and expect the core to clear well while the legs stay slightly visible after the repair.
How do I tell a star break from a crack?
Look for the pit. A star break has a crater at the center where glass is missing and every line starts from that one point. A crack has a single line, often with no crater anywhere along it. If you find no pit at any point on the line, you are looking at a stress crack, which is a different problem entirely.
Why can I still see my repaired star break in certain light?
Because a small amount of air stayed at the tapered end of one or more legs. Resin has to travel into a void that narrows to nearly nothing, and whatever it cannot reach still reflects light. That is a normal outcome, not a failed repair. The repair is judged on whether it stopped the spread and restored strength.