CPR Compression Depth Explained: How Deep to Push for Adults, Children, and Infants

For an adult in cardiac arrest, chest compressions should be at least 2 inches (5 cm) deep, and the most common error is not pushing too hard but pushing too shallow. Understanding CPR compression depth explained by age group, from adults to infants, is one of the most useful things a rescuer can learn, because depth is the part of CPR people consistently underdo and the part you cannot judge reliably by instinct.

Children and infants need less depth than adults, and body size changes how you apply the technique without changing the target. This article covers the recommended depths, the physiology behind them, the mistakes that make compressions ineffective, how to adjust for smaller patients, and how hands-on practice builds the right feel.

The Recommended Depths by Age Group

Depth targets are tied to the size of the patient's chest. As of 2026, the American Heart Association (AHA) guidance, which the American Red Cross follows closely, breaks down like this:

Adults and adolescents: at least 2 inches (5 cm), without going beyond about 2.4 inches (6 cm).

Children (about 1 year to puberty): about one-third the front-to-back depth of the chest, which is roughly 2 inches (5 cm).

Infants (under 1 year): about one-third the depth of the chest, which is roughly 1.5 inches (4 cm).

A quick reference you can screenshot:

Adult or adolescent: 2 to 2.4 inches (5 to 6 cm), two hands, heel of one hand on the lower half of the breastbone

Child: about 2 inches (5 cm), one or two hands depending on size

Infant: about 1.5 inches (4 cm), two fingers or two thumbs

All ages: 100 to 120 compressions per minute, full recoil after each push

Notice that the adult range has both a floor and a ceiling. The minimum matters because shallower compressions move too little blood. The upper limit exists because pushing much deeper adds injury risk without a clear benefit.

The Red Cross and AHA align closely on these numbers, so the depth you learn in either course will serve you in an emergency regardless of which card you hold. If you're weighing the two, this breakdown of American Red Cross and American Heart Association CPR certification covers how they differ. Guidelines are reviewed periodically, and wording can shift between updates. If you need the exact current phrasing, for example for a workplace policy or instructor materials, check the latest AHA guidelines and Red Cross course materials directly. Your instructor will teach whichever version is current for your course.

Why Depth Determines Whether Compressions Work

When the heart stops, it no longer pumps blood on its own. Compressions replace that function by pressing the heart between the breastbone and the spine, forcing blood out toward the brain and the heart muscle itself. The deeper you push within the target range, the more blood moves with each compression. The brain can tolerate only minutes without that flow, so every compression counts. For the full sequence around depth, see this step-by-step guide on how to perform CPR on adults.

Recoil: the half of the cycle people forget

Recoil is the chest returning fully to its normal position after each push. The heart refills with blood during that release, so if you lean on the chest between compressions, the heart has little to pump on the next one. Depth and recoil work as a pair: push to the full target, then let the chest rise completely without lifting your hands off it.

The cost of too shallow and too deep

Shallow compressions generate little circulation, which means effort without much benefit. Overly deep compressions raise the chance of injury, including rib fractures and damage to the chest. Rib fractures are common in CPR, particularly in adults, and they are not a reason to stop. A broken rib can heal; cardiac arrest without effective circulation usually cannot be survived.

Depth is one metric among several

High-quality CPR is a bundle of measures that work together:

Depth within the correct range for the patient's age

A rate of 100 to 120 compressions per minute

Full chest recoil

Minimal interruptions, sometimes tracked as chest compression fraction, the share of total resuscitation time spent actually compressing

A perfect depth means little if you pause for long stretches, and a perfect rate means little if each push is only an inch. The goal is to get all of them right at once, which is harder than it sounds and is the reason practice matters.

Common Depth Mistakes and Why They Happen

The dominant error is going too shallow. Two forces drive it: fear of hurting the person, and fatigue. Both are understandable, and both are fixable once you know they are coming.

Fear of causing injury

Many first-time rescuers hold back because they worry about breaking ribs. It helps to reframe this: cracked or broken ribs do not mean you did CPR wrong. They are a known and frequent consequence of compressions that are deep enough to work. Rescuers acting in good faith, following their training, are doing what the situation demands. The person you are helping has no pulse and is not breathing normally, so the realistic choice is between effective compressions with possible injury and ineffective compressions with a much worse outcome.

The wrong surface

A bed, sofa, or soft mattress absorbs part of your force, so you can push your hands down 2 inches while the chest itself moves far less. When possible, move the person to a firm, flat surface such as the floor. If moving them would cause long delay, start compressions where they are and relocate when help arrives.

Poor body position

Technique problems quietly cap your depth:

Bent elbows turn compressions into an arm workout, and your arms tire quickly.

Kneeling too far from the chest prevents you from stacking your shoulders over your hands.

Not using body weight forces you to rely on muscle strength alone.

The fix is to kneel beside the chest, lock your elbows, position your shoulders directly above your hands, and push straight down by hinging at the hips.

Fatigue arrives early

Compression quality can start to decline within about two minutes, often before the rescuer feels tired. If another trained person is present, swap roles about every two minutes, which lines up with the rhythm check prompts from an AED. Make the swap quickly, in under about 10 seconds, so the pause stays short. If you're unsure whether to use compressions alone or add breaths, this comparison of hands-only CPR vs traditional CPR can help.

Adjusting Depth for Children, Infants, and Different Body Sizes

The principle behind pediatric depth is proportion. Rather than memorizing separate numbers, think of the target as about one-third of the chest's front-to-back depth. Imagine the chest as a thick book lying on its side, with the cover being the breastbone and the back cover being the spine. Your compression should press in roughly one-third of that thickness, so that a full push leaves two-thirds of the chest remaining.

Children

For a child, use one or two hands depending on the child's size and what lets you reach the target depth with control. A small child may need only the heel of one hand, while a larger child may need two hands stacked like an adult. The depth goal is about 2 inches, or one-third of the chest, and the rate remains 100 to 120 per minute.

Infants

Infant technique depends on how many rescuers are present:

One rescuer: use two fingers placed on the center of the chest, just below the nipple line.

Two rescuers: use the two-thumb encircling technique, wrapping both hands around the chest with your thumbs side by side on the lower half of the breastbone.

The target is about 1.5 inches (4 cm). Because the infant chest is so small, a depth that feels gentle can still be correct. Allow full recoil, and keep your fingers or thumbs in contact with the chest. For a full walkthrough, see this guide to infant CPR techniques, and parents may also want to look at infant CPR training for parents.

Smaller and larger adults

Body size among adults does not change the target. A petite adult and a large adult both need at least 2 inches, not less than 2 and not far above 2.4. It can be tempting to adjust by feel, pushing lighter on someone who looks frail or heavier on someone large, but feel alone is unreliable. Aim for the adult range every time and trust the standard rather than your impression of the person.

How to Learn the Right Depth: Feedback Manikins and Hands-On Practice

Almost nobody can estimate 2 inches of chest movement accurately without practice. The force required is greater than most people expect, which is why untrained rescuers so often undershoot. Reading about depth helps you understand it, but it does not give your hands the memory.

What feedback devices do

Training manikins commonly use a clicking mechanism that signals when you have reached adequate depth, and many classrooms use manikins with light or screen-based feedback that shows depth, rate, and recoil in real time. You see immediately if you are too shallow, too fast, or leaning on the chest. Some AEDs and smartphone apps also provide coaching prompts during a real or simulated event, though your trained technique is what makes those prompts easy to follow.

Why practice beats reading

Muscle memory and confidence come from repetition under correction. After a few rounds on a feedback manikin, the right force feels familiar, and that familiarity is what keeps people from freezing or pushing timidly in a real emergency. If you want to make the most of a class, these strategies for hands-on CPR training classes are a good starting point.

Training at Taylored Instruction

Taylored Instruction teaches CPR, BLS, and First Aid as an authorized American Red Cross Licensed Training Provider and an AHA Training Site, so you can choose the certification your employer or program requires. Classes run in the Vancouver, WA and Portland metro area and in San Luis Obispo, CA. Instructors coach individually, watching your hand position, posture, and depth, and correcting them in the moment rather than leaving you to guess.

Skills fade faster than cards expire

CPR certifications typically last two years, but research on skill retention has consistently shown that compression quality can decline within months of training. Refreshers, and periodic practice in between, keep your depth and rate where they need to be. See how long CPR certification lasts for renewal timelines.

Push Hard Enough: The Depth That Gives Someone a Chance

For an adult, at least 2 inches is the number to carry with you. Pushing hard and fast, letting the chest recoil, and keeping interruptions short gives a person in cardiac arrest the best chance of survival until emergency responders take over. Hesitation costs more than a cracked rib ever will.

Don't wait until an emergency happens. Get the life-saving certification you need today. Register for a CPR, First Aid, or Lifeguarding class and gain the confidence and skills to respond when it matters most. For CPR and BLS in particular, practicing with feedback in a hands-on session is the fastest way to learn what the right depth actually feels like.