Simple Timer: Interval HIIT

More than a timer — a training partner. Simple Timer AI structures any interval workout with smart voice coaching and heart rate zones that adapt to your effort, so every cue lands at exactly the right moment. Build multi-round sessions from any combination of work, rest, warmup, cooldown, meditation, and strength steps. Set durations in seconds or minutes, connect a Bluetooth heart rate monitor to assign zones per step, and let the engine handle every transition, countdown beep, and coaching cue automatically. On iPhone, Live Activities bring your progress to the Lock Screen and Dynamic Island. Audio routes to AirPods, a speaker, or your car. FREE — NO SUBSCRIPTION REQUIRED - Full interval timing with multi-round, multi-step structure and voice announcements - Live BPM and zone-based guidance with a compatible heart rate monitor - Up to five saved timers (see app for current limits) - Countdown beeps, chimes, and vibration where supported SIMPLE TIMER PRO — OPTIONAL SUBSCRIPTION - AI-assisted timer creation: describe a workout, get a ready-to-run plan - Adaptive coaching cues that respond to your BPM, zone, time in step, and workout context - Custom BPM targets per step - Premium cloud voices via third-party TTS (sign-in required; rate limits apply) - Offline timer downloads with cached coaching audio - Unlimited saved timers and full workout history with exports WEB COMPANION Design and manage timers at simple-timer-ai.com, sign in on your phone, and run them anywhere. Privacy Policy: simple-timer-ai.com/privacy Terms of Service: simple-timer-ai.com/terms