Your daily energy curve
Plan focused work and breaks with an estimate of your daily rhythm. The model uses your sleep and other available Apple Health data.
How the energy curve works →
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What Circadian shows
The energy curve in the app, in widgets and on Apple Watch, plus your sleep window, alarm and a look back at your sleep.
Widgets and Apple Watch
See your curve on the Home Screen, peaks and dips on the Lock Screen and your sleep window in StandBy. The Watch app brings your curve to your wrist.
Set up your widgets →
Sleep window and alarm
Choose your earliest and latest wake time. Circadian calculates an alarm time within that window. Optionally, Apple Watch uses movement cues to help choose when to wake you.
Set up your smart alarm →
A look back over 14 or 30 days
See when you fell asleep and woke up over 14 or 30 days and whether HRV, resting heart rate and respiratory rate are within your usual range. You can still compare your energy curve with a date range.
Understand sleep data and trends →
The energy curve is a model-based estimate, not a measurement of your actual performance or medical advice. Smart Wake does not detect sleep stages in real time.
Try it for seven days, then unlock it once
Every feature is included in the trial. Afterwards, you decide whether to unlock Circadian permanently.
For seven days you can use every feature for free. After that, unlocking costs €6.99 once; there is no subscription.
Price in the German App Store. In other countries, the app displays your local price.
Requires iPhone with iOS 26 or later. Optional Apple Watch with watchOS 26 or later.
Download on the App StoreFrequently asked questions
Which devices does Circadian support?
Circadian requires iOS 26 or later. The optional Apple Watch app requires watchOS 26 or later. You do not need an Apple Watch to use the iPhone app.
How accurate is the energy curve?
Circadian estimates your energy pattern using a model based on sleep research. Your sleep and other available Health data personalize the curve. It does not measure your actual performance or replace a medical assessment.
Do I need an Apple Watch or a specific sleep tracker?
No. Circadian can use sleep data from any source that writes to Apple Health. Without suitable data, the app uses default values. The optional wrist alarm requires an Apple Watch.