CPR Beat keeps your chest compressions at the right pace when it matters. One big button starts a loud, steady click at 100, 110 or 120 compressions per minute. Switch to 30:2 and the app counts thirty compressions, warns before the last five, then paces two breaths. A countdown reminds the team to switch rescuers, and the elapsed CPR time with the start time stays on screen for handover to paramedics. Works fully offline. No account, no ads, no analytics, no network permission, no data collected. Free and open source (GPL-3.0). Features • Rates 100 / 110 / 120 bpm, changeable mid-session without losing the beat • Compressions-only or 30:2 mode with a breath pause of 3–8 seconds • Rescuer-switch countdown: off, 1, 2, 3 or 5 minutes, with a flash and SWITCH RESCUER banner • CPR elapsed time and start time, kept after STOP • Plays through the alarm channel, so it is heard in silent mode; optional automatic maximum volume • Three click sounds; settings remembered between launches • Dark, high-contrast screen designed for gloves and daylight Interface in English and Russian: follows the phone language, or pick one in Settings. The 100–120 compressions per minute range follows current resuscitation guidelines (AHA 2025, ERC 2025). Important: CPR Beat is a pacing aid only. It is not a medical device and does not diagnose, treat, cure or prevent any medical condition. It is not a substitute for certified CPR training. In an emergency, call your local emergency number first and follow the dispatcher's instructions. Consult a healthcare professional for medical advice. CPR Beat is an independent open-source project. It is not affiliated with, sponsored by, or endorsed by the American Heart Association or the European Resuscitation Council.