How to break a car window in an emergency, and when a tool will not
The short answer
To break a car window in an emergency, use a spring-loaded or hammer-style window breaker on a side window, low and near a front corner. Tempered glass shatters into small pieces; laminated glass, used in windshields and some side windows, will not break through. In water, unbuckle, open or break a window and get out first.
Scenes marked as illustrations show how the product is used; the product photos show exactly what ships.
In short
Window breakers work on tempered glass, which shatters into small pieces. No tool in AAA’s test broke through laminated glass.
Windshields are laminated, and a growing number of side windows are too. Read the label in the corner of each window now, not in an emergency.
Strike a tempered side window low and near a front corner, never in the middle, and never the windshield.
In a sinking car: seatbelts off, window open or broken, out immediately, children first. Do not stop to call for help.
Keep the tool where the driver can reach it after a crash, not in the glove box or the trunk.
In this guide+
A window breaker is one of the few tools that works in seconds or not at all,
and which of the two depends on the glass in front of you. The time to find out
is now, parked, with a coffee in your hand: which windows in your car will
shatter, where the tool is, and what you would do first if the car went into
water.
First, know which of your windows will break
Car glass comes in two kinds, and they fail in opposite ways.
Side windows used to be tempered almost without exception. That is changing,
because laminated side glass helps keep people inside the car in a rollover.
So check your own car rather than assuming. Every window carries a small label
etched into a lower corner.
Read the word on the label, not the code beside it: a mark such as AS2 appears
on both kinds of glass. Make a note of which windows are tempered, and tell
whoever else drives the car.
What the tests found
The one independent test most often quoted settles two questions at once:
whether these tools work, and which kind works better.
The spring-loaded result makes sense once you picture the situation. A
spring-loaded punch only has to be pressed against the glass until it fires,
which works with a seatbelt on, in a cramped seat, at an awkward angle. A hammer
needs room to swing and a firm strike.
How to break a tempered side window
Pick a side window you know is tempered, as close to you as possible. Never
the windshield.
Turn your face away from the glass.
Place the tip low on the window, near the front corner.
Press a spring-loaded tool firmly until it fires, or strike sharply with a
hammer-style tool.
Use the tool, not your hand, to push the broken glass out of the frame before
you climb through.
If the car is in water: seatbelts, windows, out, children
A car that goes into water gives you less time than most people imagine, and
the instinctive first moves — calling for help, waiting for the doors — are the
wrong ones.
Open the window before you break it, if it still opens.
If it does not, break it, and go out through it. A spring-loaded tool matters
most here.
Cutting a jammed seatbelt
A belt that will not release after a crash, or with the car on its side, is the
other reason to keep a tool within reach. The blade on an escape tool sits
recessed in a slot: hook the slot over the belt and pull it across.
Where to keep the tool
A tool you cannot reach while belted in, after a crash, is no tool at all.
A mounted tool stays in one car. A keychain tool goes with the keys into
whichever car you are driving, which suits a household that shares cars or a
driver who rents them.
Test it once, so you know it fires, and so you know how hard you have to press.
Locked out is not an emergency for a window breaker
If the problem is keys locked in a parked car, breaking the glass costs you a
window and gains nothing a technician cannot do without damage. We connect you
with a local one through our
car lockout service. The exception
is a person or an animal locked inside on a warm day.
A child or a pet locked in a hot car
That is an emergency, and it starts with a phone call, not a tool.
Whether you may then break a window yourself depends on the state you are in,
and the laws that allow it attach conditions.
Call 911 first, follow the operator’s instructions, and check your own state’s
law in advance rather than on the day. This guide describes the rules; it is
not legal advice.
The gear this guide mentions
Each product page lists what it fits and what it does not, the delivery estimate for your order and the return terms, before you pay.
On tempered glass, the good ones do. In AAA’s test of escape tools, most broke tempered side glass, the spring-loaded kind more reliably than the hammers, and none broke through laminated glass. Find out which of your windows are tempered before you rely on one.
Can a window breaker break a windshield?
No. Windshields are laminated glass, which cracks but holds together, and escape tools do not break through it. Use a side window, and check in advance that it is tempered rather than laminated.
How do I know if my car windows are laminated or tempered?
Read the label in a bottom corner of each side window: it should say tempered or laminated. Front and rear side windows can differ on the same car. If a window has no label, or the label does not say, ask the manufacturer.
Where should you hit a car window to break it?
Low on a tempered side window and close to the front corner, not in the middle of the glass. A spring-loaded tool only has to be pressed firmly against the glass; a hammer-style tool needs a sharp swing, which is much harder in a cramped seat or under water.
Should you call 911 if your car is sinking?
Not first. A car in water gives you very little time to get out through a window, and a phone call spends that time while no rescuer can reach you. Get everyone out, then call.
Is it legal to break a car window to save a child or a dog?
It depends on the state. Many states protect people who break into a car to rescue a child, and some an animal, usually only on conditions such as calling 911 first, using no more force than needed and staying until help arrives. Call 911 before anything else and check your state’s law; this is not legal advice.
I locked my keys in the car. Should I break a window?
No. A lockout is not an emergency for a window breaker: a lockout technician opens the door without damage. If a child or a pet is locked inside on a warm day, call 911 first.
Where these statements come from
Anything numeric or regulatory on this page carries the document it was read from and the date it was checked against it. A claim with no source is left off the page.
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AAA’s research describes most vehicle side windows as tempered glass, which shatters into small pieces when broken, while laminated windows have a layer of plastic sandwiched between two panes of glass, are much more impact resistant and are kept intact by the plastic even when cracked.
The same report notes that laminated glass is the standard material for windshields, because of the greater need for impact protection and shatter resistance.
AAA reports that an increasing number of new cars have laminated side windows, a nearly unbreakable glass meant to lessen the chance of occupant ejection during a collision.
Federal Motor Vehicle Safety Standard No. 226 sets requirements for ejection mitigation systems that reduce the likelihood of occupants being ejected through side windows in rollovers or side impacts. It does not require laminated glass: NHTSA anticipated that manufacturers would meet it with side curtain air bags, possibly supplemented with advanced glazing.
AAA advises checking the label in the bottom corner of each side window, which should indicate whether the glass is tempered or laminated, and contacting the vehicle manufacturer if there is no label or it does not say. Some vehicles have different glass in different places, such as tempered rear side windows and laminated front ones.
Of six escape tools AAA researchers tested, three spring-loaded and three hammer-style, four were able to shatter tempered glass and none were able to break laminated glass, which stayed intact even after being cracked. Over multiple rounds of testing, the spring-loaded tools were more effective at breaking tempered windows than the hammer-style tools.
Guidance published for emergency dispatchers says that to break a tempered side window reliably, you have to concentrate the force in a small area low on the window, and close to the front of the window if you can.
Professor Gordon Giesbrecht of the University of Manitoba teaches SWOC for a vehicle in water: Seatbelts off, Windows open or broken, Out immediately, Children first (oldest to youngest). He notes that a sinking vehicle may float on the surface for up to 3 minutes, but that you only have 1 minute to exit it safely.
The same guidance warns against touching your cell phone: you have about one minute to exit through your window before water pressure prevents opening the windows, a phone call will only waste valuable time, and rescue personnel cannot get to you within one minute.
Waiting for the vehicle to fill with water so the pressure equalizes and a door can be opened is not a plan: by that point, Giesbrecht notes, many people will have drowned.
Palm Beach County’s guidance notes that electric windows may work for a short period of time after a vehicle enters the water, and should be opened as quickly as possible.
Every tool in AAA’s test cut through seat belt material on every attempt; four averaged less than 2.5 seconds per cut, while the two slowest averaged 13.5 and 23.0 seconds.
Palm Beach County’s guidance is to keep the tool within reach — on a keychain, mounted on the driver’s side door or in a covered center console — and not in the glove box or the trunk.
AAA suggests testing a tool ahead of time on a softer surface such as a piece of soft wood: it works if the tip strikes the surface and leaves a small indent.
Kids and Car Safety’s advice if you see a child or a pet alone in a vehicle: do not wait for the driver to return, call 911 right away, and the 911 operator can give you instructions on how to care for the child or pet.
Kids and Car Safety counts 26 states with Good Samaritan laws specific to hot car rescue; some protect only children, while others also cover adults and pets.
Florida’s law is a typical example of the conditions attached: immunity for damage to the vehicle applies only if the person finds the vehicle locked, believes in good faith that the occupant is in imminent danger, makes sure law enforcement or 911 is called before entering or immediately after, uses no more force than necessary, and stays until first responders arrive.
