About CircadianHub: How the Sleep Calculators Work

CircadianHub is a free set of sleep planning tools and guides. This page explains what the site does and its limits.

What the tools do

The CircadianHub works out bedtimes or wake-up times based on sleep cycles of roughly 90 minutes, with an allowance for the time it takes to fall asleep. The Jet Lag Planner builds a simple adjustment schedule for time zone changes. Both are planning aids, not diagnostic tools.

Why 90-minute cycles?

Sleep moves through repeating cycles that average about 90 minutes but vary between people and through the night. We use 90 minutes as a practical estimate. See our article on how sleep cycles work for the details and limits.

About our articles

Our guides are general information for readers, based on published sleep research and widely used guidelines. They are not medical advice and are not a substitute for a doctor.

Advertising and privacy

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Contact

Questions or corrections are welcome at circadianhub@gmail.com.

Medical disclaimer: Content on this site is for general information only and is not medical advice.