Kairo: Circadian Rhythm
Plan your day by your rhythm
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Stop fighting your clock. Kairo learns your sleep, HRV and chronotype to find your real peak windows, then plans focus, workouts and rest around your biology.
Most apps tell you what already happened. Kairo looks forward — it maps the day you haven't lived yet and shows you the right time to do each thing.
Your body runs on a circadian rhythm: focus, creativity, physical strength and the urge to sleep each peak at different hours. Kairo estimates that rhythm from your sleep timing, heart-rate variability and chronotype, turns it into a live energy curve, and proposes a day that works with your biology instead of against the clock on the wall.
WHAT KAIRO DOES
• Estimates your circadian phase from Apple Health signals and a short science-based onboarding (MCTQ chronotype).
• Draws a live energy curve — when your analytic focus, your creative insight and your body are each at their best.
• Finds your real peak windows and suggests what to do in each: deep work on the cognitive peak, creative work at the off-peak hour, strength near the late-afternoon body-temperature max.
• Proposes a plan around your existing calendar — and never writes a block until you tap to confirm.
• Learns. The more nights it sees, the more it personalizes — all on your device.
PRIVATE BY CONSTRUCTION
Your raw health data is processed on your iPhone and is never uploaded, sold, or used for advertising. The cloud is never in the loop for a recommendation. Optional cross-device sync stores only an encrypted blob of model settings — never raw sleep, heart-rate or HRV streams. See https://kairoapp.xyz/privacy.
REAL CHRONOBIOLOGY, NOT HOROSCOPES
Kairo runs on the same models sleep researchers use — MCTQ chronotyping, the two-process model of sleep regulation, and the light phase-response curve. It shows honest windows, not fake-precise minutes.
KAIRO PRO
Kairo is free to use: the energy curve, manual logging and daily guidance. Pro unlocks:
• Active planning — add your best blocks to your calendar (propose → confirm)
• Travel, jet-lag, eating-window and morning-light timing
• Cross-device encrypted sync
• Generative soundscapes and the high-fidelity ambient field
Pro is an auto-renewing subscription:
• Kairo Pro Weekly — $6.99/week, with a 3-day free trial
• Kairo Pro Monthly — $9.99/month, with a 7-day free trial
• Kairo Pro Yearly — $39.99/year, with a 7-day free trial
Your free trial converts to a paid subscription unless cancelled at least 24 hours before it ends. Payment is charged to your Apple ID; manage or cancel anytime in the App Store.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://kairoapp.xyz/privacy
Kairo estimates circadian timing to help you plan your day. It is not medical advice and does not diagnose or treat any sleep or health condition.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, Anton Butser, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Anton Butser
- Size
- 13.7 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
English and 2 more
- English, Russian, Spanish
- Age Rating
9+
- 9+
- Contains
Health or Wellness Topics
- In-App Purchases
Yes
- Kairo Pro · Weekly $6.99
- Kairo Pro · Yearly $39.99
- Kairo Pro · Monthly $9.99
- Copyright
- © 2026 Anton Butser