CPR Compression Rhythm Timer
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Common uses for a cpr compression rhythm timer
- Practising compression rhythm after training
- Timing the two-minute rescuer swap
- Refresher practice on a manikin
- Instructor-led practice sessions
The American Heart Association recommends chest compressions at a rate of 100 to 120 per minute[1]. This page is a rhythm and interval aid for people practising or refreshing a skill they have already been taught. It is not a substitute for certified training, and reading it does not prepare anyone to perform CPR.
Two minutes is the interval at which rescuers should swap where more than one is available, because compression quality falls measurably with fatigue well before the rescuer notices it. Timing that swap is the specific thing this page is useful for.
Get trained. This page is not training.
CPR is a physical skill that requires hands-on instruction and practice on a manikin with feedback. Certified courses are widely available, often in a few hours, and they are the only appropriate way to learn it.
If you are facing an emergency right now, call your emergency number immediately. Dispatchers in many regions can talk a caller through compressions in real time, and that is the correct source of instruction in that moment — not a web page.
Why rate and swapping matter
Compressions that are too slow do not circulate enough blood; too fast and the chest does not recoil fully between compressions, which also reduces circulation. The 100 to 120 window exists because both errors are common and both reduce effectiveness.
Rescuer fatigue degrades depth and recoil within about two minutes, and the rescuer is usually the last to notice. Swapping on a timed interval rather than on how tired someone feels is what keeps quality up over a long resuscitation.
The ratio and the alternative
Thirty compressions to two rescue breaths is the standard adult ratio for a trained rescuer. Compression-only CPR is recommended for untrained bystanders and is far better than doing nothing.
Guidelines are revised periodically and differ in places between resuscitation councils. Take the current guidance from your local resuscitation council or the course you attend, not from a general reference.
AHA figures for adult CPR[1]. Guidelines are revised — take current guidance from your local resuscitation council.
| Element | Value | Note |
|---|---|---|
| Compression rate | 100–120 / min | Too fast prevents full recoil |
| Compression to breath ratio | 30:2 | Adult, trained rescuer |
| Rescuer swap | Every 2 min | Quality falls before fatigue is felt |
| Compression-only CPR | Continuous | Recommended for untrained bystanders |
| Interruptions | Minimise | Every pause reduces circulation |
- This page is a practice aid for people already trained. It is not training and does not prepare anyone to perform CPR.
- In an emergency, call your emergency number first — dispatchers can give real-time instructions.
Source: American Heart Association CPR guidelines — compression rate and ratio
Sources
- American Heart Association CPR guidelines — compression rate and ratio , American Heart Association (Verify current guidelines) — accessed 2026-07-28