Circadian Rhythm Calculator
Explore sleep timing in relation to your daily routine, light exposure, and regular wake time.
Circadian Rhythm Calculator
Your circadian rhythm is more than a clock
The circadian system responds to light, behavior, meal timing, activity, and regular sleep timing. A calculator cannot measure your internal body clock, but it can help you think through a more consistent schedule.
What the circadian rhythm calculator does
Enter your usual bedtime and wake-up time to see your sleep window and a simple mid-sleep estimate. Mid-sleep, the midpoint of your sleep on free days, is a common way to describe your body clock.
Using the result
If your mid-sleep is late, you probably lean toward evenings. Light, routine and timing can nudge it. See the circadian rhythm calculator guide and the shift work guide.
Limits
It is an estimate based on what you enter, not a lab measurement.
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