How to Do CPR
Learn how to perform CPR on an adult in an emergency. Covers hands-only CPR, rescue breaths, when to use an AED, and what to do until help arrives.
Cardiac arrest kills over 350,000 Americans outside of hospitals each year, according to the American Heart Association. When someone's heart stops, brain damage begins within four to six minutes without intervention. Emergency services rarely arrive inside that window. Response times vary widely from one town to the next, and in most places you should expect to be alone with the person for several minutes at least.
That gap is where bystander CPR saves lives. The AHA reports that immediate CPR can double or triple a person's chance of survival. Yet only about 40% of cardiac arrest victims receive bystander CPR before paramedics arrive.
If you are hesitating because you are not sure you would do it right, remember that imperfect CPR is vastly better than no CPR. If someone is unresponsive and not breathing normally, they are already in the worst possible situation. You cannot make it worse by trying.
This guide covers hands-only CPR, which is what the AHA recommends for untrained bystanders. It is simple, effective, and does not require mouth-to-mouth breathing.
Check for responsiveness and call 911
If you see someone collapse or find someone unconscious, first make sure the scene is safe for you (no live electrical wires, traffic, or other hazards). Tap the person firmly on both shoulders and shout "Are you okay?" If they do not respond, call 911 immediately or tell someone specific to call. Say "You in the red shirt, call 911 now." Pointing at a specific person prevents the bystander effect where everyone assumes someone else is calling. If you are alone, put your phone on speaker and call 911 while you begin CPR. The dispatcher will stay on the line and guide you through the process if needed.
Heads up: Do not waste time checking for a pulse unless you are trained to do so. Pulse checks are unreliable for untrained rescuers and waste precious seconds. If the person is unresponsive and not breathing normally (no breathing, gasping, or only occasional gasps), begin CPR immediately.
Start compressions where the person is
Roll the person onto their back and kneel beside their chest, roughly at nipple level. A firm surface is better, because a mattress absorbs some of the force you put into the chest. But do not move them to go and find one. This is the part that changed. Older advice told you to get the person onto the floor first. The 2025 adult resuscitation guidelines reversed that, because the delay involved in moving someone costs more than the soft surface does. If they collapsed on a bed, start on the bed and push harder to make up the difference. Remove any thick clothing covering the chest if you can do it quickly, but do not waste time with zippers, bras, or buttons that take more than a few seconds. Compressions work through clothing. If the person is wearing a heavy winter coat, open or remove it if possible because the bulk absorbs compression force and reduces effectiveness. Speed matters more than perfection here. Every second without compressions is a second without blood flow to the brain.
Place your hands in the correct position
Put the heel of one hand on the center of the person's chest, on the lower half of the breastbone (sternum). Place your other hand on top of the first, interlocking your fingers. Keep your fingers lifted off the chest so that only the heel of your bottom hand is pressing on the sternum. Straighten your arms and lock your elbows. Position your shoulders directly above your hands so you can push straight down using your body weight rather than arm strength alone. This position is critical for effective compressions and for preventing fatigue. A common mistake is placing your hands too high (on the upper chest near the collarbone) or too low (on the soft area below the sternum). Too high reduces compression effectiveness. Too low can push on the stomach and cause vomiting. The correct spot is between the nipples, on the hard bone in the center of the chest.
Push hard and fast: 100 to 120 compressions per minute
Press down at least two inches into the chest, and no more than about 2.4 inches. The 2025 AHA guidelines put new emphasis on that upper limit, because going deeper than that adds injury risk without moving more blood. Push hard. It takes more force than you expect, and you may feel or hear ribs cracking. This is normal in CPR and does not mean you should stop. Cracked ribs heal. Cardiac arrest without CPR does not. Push at a rate of 100 to 120 compressions per minute. The beat of the song "Stayin' Alive" by the Bee Gees matches this tempo perfectly. So does "Baby Shark" or the Imperial March from Star Wars. Let the chest fully recoil (come back up completely) between each compression. Do not lean on the chest between compressions. Full recoil allows the heart to refill with blood between pushes.
Continue without stopping until help arrives
Do not stop compressions except to switch with another rescuer or if the person shows obvious signs of life (moving, breathing normally, coughing). CPR is physically exhausting. Compression quality degrades after about two minutes even if you do not feel tired yet. If another person is available, switch every two minutes. The person being relieved should count to ensure minimal interruption during the switch. Aim for less than ten seconds of interruption during the handoff. If you are alone, keep going. Tired CPR is still better than no CPR. Only stop if professional help arrives and takes over, the person clearly regains consciousness, or you are physically unable to continue. Expect to be performing CPR for five to fifteen minutes before paramedics arrive. That feels like a very long time when you are doing it. Your arms will burn, your back will ache, and you will wonder if it is working. Keep pushing. CPR does not restart the heart by itself in most cases. It keeps oxygenated blood circulating to the brain until a defibrillator or advanced medical intervention can restore a normal heart rhythm. You are buying time.
Use an AED if one is available
An AED (Automated External Defibrillator) is a device that can shock the heart back into a normal rhythm. They are found in many public buildings, airports, gyms, schools, and offices, usually in a wall-mounted case. If someone brings you an AED, turn it on and follow the voice prompts. The device tells you exactly what to do. Open the pads, peel the backing, and place them on the person's bare chest as shown in the diagram on the pads (one on the upper right chest, one on the lower left side). The AED will analyze the heart rhythm and tell you whether a shock is advised. If it says shock, make sure nobody is touching the person, press the shock button, then immediately resume CPR. AEDs are designed for untrained users. You cannot shock someone who does not need it because the device analyzes the rhythm first.
Good to know: Send someone to look for an AED as soon as you begin CPR. Do not stop compressions to search for one yourself. If a bystander brings one, they can set it up while you continue chest compressions. Minimize any pause in compressions.
Know what hands-only CPR cannot cover
Hands-only CPR (compressions without rescue breaths) is recommended for untrained bystanders performing CPR on adults. It is effective because the blood still contains oxygen for several minutes after cardiac arrest, and compressions circulate that oxygenated blood to the brain. For drowning victims, children, and infants, rescue breaths are more important because the cause is often respiratory (not enough oxygen) rather than cardiac. If you are trained and willing, give two rescue breaths after every 30 compressions: tilt the head back, lift the chin, seal your mouth over theirs, and blow for one second until you see the chest rise. If you are not trained or not comfortable with rescue breaths, continuous hands-only compressions are still highly effective for adult cardiac arrest. Child CPR (ages 1 to puberty) uses the same technique with less force. Use one hand instead of two on a smaller child and compress about two inches, which is roughly a third of the depth of their chest. Infant CPR (under age 1) changed in 2025. The 2025 AHA and American Academy of Pediatrics guidelines dropped the old two-finger method, because a multicenter study found it consistently failed to reach an adequate depth. Use the heel of one hand instead. If a second person is there to manage the airway, you can wrap both hands around the infant's chest and compress with your thumbs, which works better still. Aim for about one and a half inches, again roughly a third of the chest. For both children and infants, rescue breaths are more important than for adults because the underlying cause is more likely to be a breathing problem rather than a heart problem. One more addition from the 2025 guidelines is worth knowing. If you suspect an opioid overdose, give naloxone as soon as someone can put it in your hands, but give it alongside compressions rather than instead of them. Naloxone reverses the drug. It does not restart a heart that has already stopped, so the compressions carry on either way.
CPR is not complicated. Check, call, push. Those three actions are all you need to remember. If someone collapses and is not breathing normally, call 911 and start pushing hard and fast on the center of their chest. Keep going until professional help arrives and takes over. The hardest part is not the technique. It is the decision to act. If you find yourself hesitating, the thing to hold onto is that the person is already in cardiac arrest. They will die without intervention. Anything you do is better than standing back. Consider taking a formal CPR certification course through the Red Cross. A short in-person class gives you hands-on practice and covers scenarios this guide cannot replicate. But even without formal training, the steps in this guide can save a life.
Questions we get asked about this
Answers from experience, not a textbook.
You may crack ribs. This is common and expected, especially in older adults. Cracked ribs heal in a few weeks. A person in cardiac arrest will die within minutes without CPR. The risk of rib injury is vastly outweighed by the benefit of circulating blood to the brain. You cannot make a cardiac arrest victim worse by performing CPR. If they are unresponsive and not breathing, they need compressions regardless of the risk of minor injury. You might also see the person gasp, make gurgling sounds, or even vomit during CPR. These are reflexes, not signs of recovery. Do not stop compressions for gasping. If the person vomits, turn their head to the side to clear the airway, wipe the mouth if you can, and resume compressions immediately.
All 50 US states and the District of Columbia have Good Samaritan laws that protect people who provide emergency care in good faith. They cover the ordinary mistakes of someone doing their best in an emergency, and they fall away only for gross negligence or willful misconduct, meaning a conscious disregard for someone's safety rather than imperfect technique under pressure. The laws exist to encourage bystanders to help without fear of liability, and similar protections exist in most developed countries.
If a person is unresponsive (does not react when you tap their shoulders and shout) and is not breathing normally (no breath, gasping, or only occasional irregular gasps), they need CPR. Do not wait to see if they "come around." Do not spend time checking for a pulse unless you are trained. Normal snoring or heavy breathing in an unconscious person is not the same as gasping. Gasping looks like a fish out of water: irregular, infrequent, ineffective attempts to breathe. When in doubt, start CPR. If the person does not need it, they will quickly show signs of life (movement, coughing, pushing you away) and you stop. Starting CPR on someone who does not need it is far less dangerous than not starting it on someone who does.
Yes. The American Heart Association explicitly recommends that untrained bystanders perform hands-only CPR (chest compressions without rescue breaths) on any adult who collapses and is not breathing normally. Formal training is valuable for building confidence and practicing technique, but it is not required to save a life. Push hard, push fast, on the center of the chest. That is enough. The 911 dispatcher will also guide you through the steps over the phone if you are unsure. Tell them you are performing CPR and they will coach you through it in real time until paramedics arrive.