KAIRO · CIRCADIAN PERFORMANCE
Do the right thing at the right time
Kairo learns your sleep, HRV and chronotype to find your real peak windows — then plans your day around your biology, not the clock on the wall.
NOW 10:00MORNING PEAKENERGY 50%. The background reflects your current time. Estimated energy 50 percent, phase morning peak.
NOT MEDICAL ADVICE · ON-DEVICE ML
WHY KAIRO
Most apps show you numbers. Kairo shows you what to do — and when.
Sleep and mood trackers tell you what already happened. Kairo is the opposite: it looks forward, maps the day you haven't lived yet, and proposes a plan you approve with one tap.
HOW IT WORKS
Three steps. One tap to commit.
Learns your rhythm
From your sleep timing, HRV and chronotype, Kairo estimates your circadian phase — and refines it the more nights it sees.
Maps your day
It turns that into a live energy curve: when your focus, your insight and your body are each at their best.
Proposes a plan
Kairo suggests a day around your fixed meetings. It never touches your calendar without a tap.
THE WINDOWS
Not all hours are equal. Kairo knows the difference.
Analytic work on the cognitive peak. Creative work at the off-peak hour, where insight is actually better. Strength near the late-afternoon body-temperature max.
Windows shown are computed by the Kairo engine for a representative chronotype. Yours are personalized after onboarding.
THE SCIENCE
No horoscopes. Real chronobiology.
Kairo runs on the same models sleep researchers use — MCTQ chronotyping, the two-process model of sleep regulation, and the light phase-response curve.
- Roenneberg
- Borbély
- Czeisler
Your clock, estimated honestly
Kairo estimates your circadian phase from behaviour and wearable signals. It shows windows, not fake-precise minutes — honest estimates, not pseudoscience.
Built on peer-reviewed work
The same circadian science used in research — chronotype (Roenneberg), the two-process model (Borbély) and light phase response (Czeisler).
Gets sharper with you
It starts from population science and personalizes toward your own patterns over time — less the average clock, more yours.
PRIVACY
Your biology stays yours.
All the learning happens on your iPhone. Raw health data never leaves the device — no cloud model in the loop, no selling, no exceptions.
Privacy Policy →- Raw sleep, HR and HRV are processed on-device and never uploaded.
- The cloud is never in the loop for a recommendation.
- Calendar is read for free/busy only — proposed blocks are written only after you confirm.
GET KAIRO
Start timing your day.
Download it and find your peak windows today.
On-device · Private · iOS 17+