The standard compression-to-breath ratio for CPR is 30 compressions followed by 2 rescue breaths. This 30:2 ratio applies to adults, children, and infants when a single rescuer is performing CPR. The ratio changes in specific situations involving multiple trained rescuers or younger patients, but 30:2 is the number most people need to know.
The 30:2 Ratio for Adults
For any adult in cardiac arrest, you perform 30 chest compressions and then deliver 2 rescue breaths. You repeat this cycle until emergency medical help arrives or the person starts breathing on their own. Each compression should push the chest down at least 2 inches, and you should aim for a rate of 100 to 120 compressions per minute. A common reference point: that’s roughly the tempo of the song “Stayin’ Alive.”
The 30:2 ratio was adopted in 2005, replacing the previous standard of 15:2. The change was driven by a straightforward problem: every time you pause compressions to give breaths, blood pressure in the heart drops almost immediately. Longer pauses mean less blood reaching the brain and vital organs. Computer simulations showed that a 30:2 ratio optimized both oxygen delivery and blood flow, and animal studies found that return of a heartbeat occurred more often with 30:2 compared to continuous compressions alone. The goal is to keep interruptions as short as possible.
When the Ratio Changes for Children and Infants
If you’re the only person performing CPR on a child or infant, you still use 30:2. The ratio shifts when two trained healthcare providers are working together on a pediatric patient. In that case, the ratio drops to 15 compressions to 2 breaths. The reasoning is practical: with two people, one can compress while the other prepares to ventilate, making shorter cycles more efficient without sacrificing compression quality.
For newborns, the ratio is different entirely. Neonatal resuscitation uses a 3:1 ratio, meaning 3 compressions for every 1 breath. This adds up to roughly 90 compressions and 30 breaths per minute, or about 120 total events. Newborns almost always go into cardiac arrest because of a breathing problem rather than a heart problem, so more frequent ventilation is critical. If the arrest is suspected to be cardiac in origin, rescuers may switch to a higher ratio like 15:2.
Hands-Only CPR: No Breaths at All
For bystanders who witness a teen or adult suddenly collapse, the American Heart Association recommends hands-only CPR, which means continuous chest compressions with no rescue breaths. You call 911 and push hard and fast in the center of the chest without stopping. Studies have shown that hands-only CPR is as effective as traditional CPR with breaths during the first several minutes of a sudden cardiac arrest in adults.
This doesn’t apply to every situation. CPR with compressions and breaths is still recommended for infants, children, drowning victims, drug overdose victims, and anyone who collapses due to a breathing problem. In these cases, the lack of oxygen is likely what caused the arrest, so rescue breaths are essential.
How Compression Depth and Speed Matter
The ratio only works if the compressions themselves are effective. For adults, each compression needs to reach a depth of at least 2 inches. For infants and children, the target is at least one-third the depth of the chest. Compressing too shallowly is one of the most common mistakes, especially as rescuers tire over time.
Speed matters just as much. Compressing slower than 100 per minute doesn’t generate enough blood flow. Going faster than 120 per minute tends to reduce depth because the rescuer doesn’t push hard enough at higher speeds. Staying in that 100 to 120 range hits the sweet spot. Between cycles, you also need to let the chest fully recoil, meaning you lift your weight completely between compressions so the heart can refill with blood.
Minimizing Pauses Between Cycles
One of the most important principles in CPR is keeping interruptions as brief as possible. When you stop compressing to deliver breaths, blood pressure in the coronary arteries drops quickly, and it takes several compressions to build it back up. This is why pulse checks should take no longer than 10 seconds, and why the 2025 AHA guidelines stress that pauses should only happen for interventions proven to improve outcomes.
In practice, this means your two rescue breaths should be delivered quickly (about one second each) before you immediately resume compressions. If you’re untrained or uncomfortable giving breaths, continuous compressions without pausing are far better than hesitating or stopping altogether. The worst thing you can do during cardiac arrest is nothing.
Quick Reference by Situation
- Adult (single or two rescuers): 30 compressions to 2 breaths
- Child or infant (single rescuer): 30 compressions to 2 breaths
- Child or infant (two healthcare providers): 15 compressions to 2 breaths
- Newborn: 3 compressions to 1 breath
- Adult witnessed collapse (bystander): Continuous compressions, no breaths needed