Sleep Cycle Calculator
Find the best times to go to sleep and wake up.
Sleep Cycle & Bedtime Calculator
Optimize your sleep by timing your wake-up and bedtimes to natural 90-minute REM sleep cycles, waking up feeling refreshed.
Peak Rest & Recovery (9 hrs)
Recommended Adult Sleep (7.5 hrs)
Moderate Rest (6 hrs)
Power Short Rest (4.5 hrs)
Human sleep follows 90-minute circadian cycles alternating between Light Sleep, Deep Slow-Wave Sleep (restores muscles & immunity), and REM Sleep (memory & dreaming). Waking up in the middle of Deep Sleep causes grogginess (sleep inertia), while waking up at the conclusion of a 90-minute cycle leaves you energized and alert.
About Sleep Cycle Calculator
Time your sleep to match natural 90-minute sleep cycles. Wake up between cycles feeling rested.
Your files and data are processed locally in your browser memory. Never uploaded to remote servers.
Instant access with no account, no email sign-up, no passwords, and no subscription paywalls.
Powered by modern WebAssembly and native web APIs for near-instant rendering and zero latency.
Zero data retention, no user tracking cookies, and GDPR/HIPAA friendly. Your data remains strictly yours.
Fully responsive on desktop, tablet, and mobile devices without installing software or extensions.
How to Use
- Select whether you want to calculate when to wake up or when to go to bed.
- Set your target time.
- Choose from recommended bedtimes matching 5 or 6 complete sleep cycles.