Short answer: 100 to 120 compressions per minute. That's the AHA 2025 target for adults. Push hard, push fast, push deep — 2 to 2.4 inches into the chest. Full recoil between each one. Don't lean. Don't stop. That's the rule.
If you're studying for certification, this is the number that shows up on every exam. If you're standing over a collapsed adult right now, this is the number that buys the brain time until paramedics arrive. The rate sounds simple. Doing it right for ten straight minutes is harder than it looks — most people drift slow within 90 seconds and never know it. That's why the songs work. That's why mannequins have feedback meters. That's why rescuers switch every two minutes.
This guide unpacks the rate itself — where the 100 to 120 window came from, what happens at 80 or 140, why depth matters as much as speed, and how the 30:2 compression-to-breath ratio fits in. You'll also see how to keep tempo without a metronome, why full chest recoil matters more than most students realize, and the common errors that cut survival rates in half. If you want a refresher on the full sequence first, the how to perform cpr walkthrough covers scene safety, check-call-compress, and AED use.
Cardiac arrest survival drops about 10% for every minute without CPR. Bystander compressions at the right rate and depth can double or triple survival odds before EMS arrives. Speed matters. Depth matters. Consistency matters most. A perfect 100/min rate with shallow 1-inch compressions saves almost no one. A solid 110/min at 2.2 inches with clean recoil keeps the brain oxygenated long enough for defibrillation to work.
Worth knowing upfront: the AHA changed compression depth guidance over the years. The old standard was "about 2 inches." The 2020 update added the upper limit — no deeper than 2.4 inches — because going too deep causes rib fractures and reduced cardiac output. The 2025 update kept that window. So when an instructor says "push as hard as you can," they mean within that 2 to 2.4 inch range. Not harder. Not deeper.
One more thing before the details: this is the adult rule. Children and infants use a similar rate (still 100 to 120/min) but different depth and hand position. Adult means anyone who's hit puberty — roughly age 12 and up. For a smaller child or infant, the technique shifts. The rate stays the same.
The window comes from outcome data. Studies tracking thousands of out-of-hospital cardiac arrests found that survival peaked when rescuers stayed between 100 and 120 compressions per minute. Below 100, blood flow to the brain dropped. Above 120, compressions got shallower because the chest didn't have time to refill between pushes. The AHA settled on the window because both edges of it hurt outcomes.
Here's what the rate actually does. Each compression squeezes blood out of the heart and into the arteries. The chest then has to recoil so blood can flow back in and refill the heart for the next squeeze. Too slow, and not enough volume moves per minute. Too fast, and the heart doesn't have time to refill — you're pumping air, not blood.
The 30:2 ratio fits inside this rhythm. After 30 compressions, you give 2 rescue breaths, then go back to 30 more. The breaths take about 5 to 6 seconds total — that's the only acceptable pause. Everything else should be compressions. Modern cpr certification courses drill this hard because every extra second without compressions cuts coronary perfusion pressure, which is the single biggest predictor of whether the heart restarts.
Some research from the past decade pushed for compression-only CPR for untrained bystanders — no breaths at all, just continuous 100-120/min pushing. The reasoning: untrained rescuers often hesitate at the breath step, which kills compression time. The AHA endorses this for unwitnessed adult arrests when the rescuer is untrained or unwilling to give breaths. Better something than nothing. But for trained rescuers — anyone who's been through formal cpr training — 30:2 is still the standard.
The math: 30 compressions at 110/min takes about 16 seconds. Two breaths takes 5 seconds. That's a 21-second cycle. In two minutes you complete roughly 5 to 6 cycles. Then you switch with another rescuer if available. Tracking cycles is one way to know when to swap without watching a clock.
Rate gets the headlines but depth is what actually moves blood. Adult chest compressions should reach 2 to 2.4 inches (5 to 6 cm) into the chest. That's deeper than most people think — and most untrained rescuers compress at 1 to 1.5 inches, which is barely enough to register as CPR at all. Manikin feedback devices and AED pads with depth sensors exist for exactly this reason: humans guess wrong about how hard they're pushing.
What does 2 inches feel like? Picture pushing a coffee mug halfway into wet sand. Firm. Steady. With a real adult chest, you'll feel ribs flex. You may hear cracking — that's normal, and it's not a reason to stop. Broken ribs heal. A brain without oxygen doesn't. Push through it.
The other half is recoil. After each compression, the chest must spring all the way back up before you push again. Leaning on the chest between compressions is one of the most common errors instructors see. It blocks the chest from refilling with blood. Even a few pounds of lean cuts cardiac output significantly. Lift your weight enough between pushes that the chest fully expands. Don't bounce off — just release pressure.
Hand position matters here too. Heel of one hand on the lower half of the sternum, between the nipples. Other hand stacked on top, fingers interlaced and pulled up off the ribs so you're not pressing on them. Arms locked straight. Shoulders directly over your hands. Push from the hips and shoulders, not from the elbows. Bent arms tire fast and lose depth. The right how to do cpr technique uses body weight, not muscle.
Posture saves your back and your rate. If you're at floor level, kneel beside the patient with one knee near their shoulder and the other near their hip. Knees about a fist-width apart for stability. If the patient is on a bed, push the mattress to the wall first or move them to the floor — compressions on a soft surface lose 30 to 50% of depth because the mattress absorbs the force.
One detail beginners miss: the compression and release should take roughly equal time. Smooth piston motion. Down-up-down-up at 100 to 120 per minute. Not a slam-and-rest pattern. Smoothness keeps blood flowing in both phases — compression pushes it out, recoil draws it back. Jerky compressions break that rhythm and reduce output even when the rate looks right on a meter.
Rate: 100 to 120 per minute. Depth: 2 to 2.4 inches (5 to 6 cm). Hand position: heel of one hand on lower half of sternum, second hand stacked. Ratio: 30 compressions to 2 breaths for single rescuer. Two rescuers also use 30:2 for adults — unlike children, the ratio doesn't change.
Switch rescuers every 2 minutes to prevent fatigue and maintain depth. Use an AED as soon as available — defibrillation within 3 to 5 minutes of collapse is the single biggest survival driver.
Rate: 100 to 120 per minute (same as adult). Depth: about 2 inches or one-third the depth of the chest. Hand position: heel of one hand on lower half of sternum (one or two hands depending on child size). Ratio: 30:2 for single rescuer, 15:2 for two trained rescuers.
The two-rescuer ratio difference matters. Children desaturate fast and benefit from more frequent breaths when help is available. AEDs use pediatric pads or pediatric mode for kids under 8 when possible.
Rate: 100 to 120 per minute. Depth: about 1.5 inches or one-third the depth of the chest. Hand position: two fingers (single rescuer) or two thumbs encircling hands (two rescuers) on the breastbone just below the nipple line. Ratio: 30:2 for single rescuer, 15:2 for two rescuers.
Infant CPR is gentler — different hands, less force — but the same 100-120/min rate. The infant cpr walkthrough covers the full technique including back blows and chest thrusts for choking.
30 compressions at 100-120/min, then 2 quick breaths. About 16 seconds compressing, 5 seconds breathing — a 21-second cycle. Five to six cycles in two minutes. Then switch rescuers if help is available.
Still 30:2 for adults — unlike children. One person compresses, the other delivers breaths. Pre-plan the switch every 2 minutes: 'On the next breath, I'll switch.' Should take under 5 seconds total.
About 1 second per breath. Just enough volume to make the chest visibly rise — no more. Over-ventilation raises intrathoracic pressure and blocks venous return. Quick and gentle through a pocket mask or barrier device.
Once paramedics insert an ET tube or supraglottic airway, compressions become continuous at 100-120/min with one breath every 6 seconds (~10/min). No more 30:2 pausing. For lay rescuers before EMS arrives, stay on 30:2 — this rule kicks in only when trained providers take over.
Count to keep rate steady. 'One and two and three...' up to thirty, then breaths. Some rescuers count by fives. CPR training classes drill three full cycles before adding breaths just to lock in the rhythm.
Compression-only CPR is AHA-endorsed for untrained bystanders, no-barrier situations, or witnessed primary cardiac arrests. Drowning, drug overdose, and child arrests still benefit from breaths — don't skip when respiratory cause is suspected.
104 BPM. The classic CPR song. Disco rhythm matches compression tempo almost perfectly. The title is its own reminder.
99 BPM. Just under target. Sing it slightly fast and you're in the window. Strong, even beat.
110 BPM. Right in the sweet spot. Some rescuers prefer it over Stayin' Alive — same tempo, less awkward lyric for the situation.
100 BPM. Pop hit, easy to remember, sits exactly at the lower edge of the AHA window.
108 BPM. Steady, country shuffle. Easier to remember the rhythm than the lyrics — perfect for CPR.
Land your hands wrong and even perfect rate and depth won't help. The target spot is the lower half of the sternum — the breastbone — roughly between the nipples on an adult. Heel of your dominant hand goes there. Other hand stacks on top, fingers interlaced and pulled back so they don't press on the ribs. Pressing on ribs instead of sternum risks lung and liver injuries and reduces the force transferred to the heart.
Visualize a line from nipple to nipple. Your hand sits on the sternum where that line crosses it. Not higher — that's the manubrium, which doesn't compress well and risks fracturing into the airway. Not lower — that's the xiphoid process, a small bone tip that can break off and damage the liver. Lower half of the sternum. Center of the chest. Same spot you'd thump if checking ripeness on a watermelon.
Arms straight. Elbows locked. Shoulders directly above your hands so the line of force runs straight down through your wrists into the chest. Bent arms means you're pushing with biceps, which tire in 30 seconds. Locked arms means you're pushing with your whole upper body and gravity — sustainable for the full two minutes between rescuer swaps.
Knees positioned for stability. Beside the patient, not straddling. One knee near the shoulder, one near the hip, about a fist's width apart. This keeps your center of gravity low and your hands directly above the compression spot. If you're tall, scoot back slightly so your shoulders sit above your hands without leaning forward — leaning means you tire faster and compress shallower.
Common drift errors. Hands creep up toward the neck as you tire — compressing the upper sternum is much less effective. Elbows bend as fatigue sets in — depth drops 30 to 50%. Rate slows under stress — the metronome in your head goes from 110 to 80 without you noticing. The fix is rescuer rotation. Every two minutes, swap. Don't trust your own self-assessment past 90 seconds.
Surface matters too. A bed, couch, or stretcher absorbs force and steals depth. If you can move the patient to a hard floor in under 10 seconds, do it. Otherwise compress where they are and accept the depth loss. CPR in an ambulance often uses a backboard sliding under the patient for the same reason. The first american heart association cpr rule is hard surface, flat back, hands on lower sternum, arms locked.
Bystander CPR works — when it's done right. Studies of cardiac arrest survival point to five common errors that turn well-intentioned CPR into ineffective CPR. Knowing them by name helps you avoid them under pressure.
Error one: compressing too slow. Stress and adrenaline make rescuers feel like they're moving fast when they're actually drifting toward 80 per minute. Songs and metronomes solve this. Use one. Even a phone app counts beats if you have a second free.
Error two: compressing too shallow. Untrained rescuers average around 1.5 inches — well below the 2-inch minimum. Lean into it. The chest is more flexible than it feels. Trust the depth target and push to it. Bone-cracking feedback isn't a stop signal. It's the sound of effective compression depth on an elderly chest.
Error three: leaning between compressions. Even a few pounds of body weight resting on the sternum between pushes blocks chest recoil and kills cardiac output. Lift fully off — without bouncing — between each compression. Hands stay in contact with the skin, but no weight transfers down. Practicing on a manikin with recoil feedback locks this in.
Error four: pausing too long. Every second without compressions drops perfusion pressure. The only acceptable pauses are 5-6 seconds for breaths in 30:2, and under 10 seconds for AED rhythm analysis or shock. Pause to check pulse? No — modern protocols skip pulse checks entirely after the initial assessment because they waste time and provide false reassurance. Once compressions start, they stop only for breaths, AED, or rescuer swap. The cardiopulmonary resuscitation protocols all emphasize this — minimize the no-compression interval.
Error five: over-ventilating during breaths. Big, forceful breaths raise intrathoracic pressure, block venous return to the heart, and worsen outcomes. Just enough volume to see the chest visibly rise. About one second per breath. Two breaths per cycle. Move on. New rescuers tend to give huge breaths because it feels like more help — it's actually less.
One sixth error worth mentioning: stopping too early. Many rescuers give up before help arrives because they think CPR isn't working. CPR isn't supposed to restart the heart on its own — it buys time for defibrillation. Survival rates rise sharply when bystanders keep going for the full 10-15 minutes it often takes for EMS to set up the AED, shock, and continue advanced care. Don't stop until paramedics tell you to stop, or the patient starts breathing on their own.
Skill without practice fades within a few months. Studies show CPR competency drops noticeably 90 days after certification and continues falling for the next two years. That's why the AHA recommends refresher practice every three to six months, not just at the two-year renewal mark.
Practice options range from formal to free. A certified cpr classes near me course with manikin time and instructor feedback is the gold standard — typically 4 to 6 hours, $50 to $100 depending on location. Hands-on time with real chest compressions on a feedback-enabled manikin is the part that actually builds skill. Online-only courses without manikin practice don't build muscle memory the same way.
For self-practice between formal sessions, several apps and YouTube videos play metronome tones at 100 to 120 BPM. Stayin' Alive on repeat works. Set a timer for 2 minutes, find a firm pillow or rolled-up towel, and practice compressions on the floor. You won't get depth feedback without a manikin, but you'll build rate consistency and stamina. Two-minute sets are the right length because that's the actual rescuer rotation interval.
Pair practice if possible. One person compresses, the other counts cycles and calls switches. After three or four rotations the differences in rate consistency become obvious — most beginners speed up at the start of each round and slow down at the end. Identifying that drift in practice is the only way to fix it in a real arrest. Workplace CPR drills with team coordination, AED simulation, and timed handoffs are more realistic than solo manikin work and worth the time.
If you took formal certification, the card lasts 2 years. Refresher classes run 1 to 2 hours and cost less than the initial course. Many employers (hospitals, schools, first-responder agencies) require recertification on a fixed schedule. Even if you're not required to recertify, the skill perishability data argues for doing it anyway. Online-only renewal courses count for certification but don't replace hands-on practice — pair them with manikin time if you can find a free open-practice session at a local fire station or Red Cross chapter.
One last note on real-world use. If you ever have to use CPR on someone, the chest will feel different from a manikin — softer, less consistent, sometimes wet from sweat or vomit. Adrenaline will compress your sense of time. The rate will feel faster than it is. Trust your training.
Sing the song in your head. Count out loud. Switch when someone offers to take over. Don't stop until EMS arrives. The full sequence of how to do cpr is recognize, call 911, compress, ventilate, AED, repeat — and the compression rate of 100 to 120/min is the engine that makes the rest of it work.
You can hit perfect rate and still fail if depth is shallow. You can hit perfect depth and still fail if you lean between compressions. The three quality measures — 100-120 per minute, 2-2.4 inches deep, full recoil — all matter equally. Miss any one and effective output drops. The good news: practice on a feedback manikin locks in all three at once. Twenty minutes of focused practice beats twenty hours of watching videos.