Calculate the perfect bedtime or wake-up time based on your natural sleep cycles. No more groggy mornings.
Enter your wake-up time and get the best times to fall asleep based on complete 90-minute sleep cycles.
Enter your bedtime and discover the optimal alarm times so you wake feeling genuinely energized.
Built on sleep cycle research. Waking between cycles — not mid-cycle — is what stops morning grogginess.
No sign-up, no app download, no subscription. Enter your time and get instant results — every time.
Learn the science behind better sleep with our in-depth guides
Find out exactly how many hours of sleep you need by age, lifestyle, and health — backed by sleep science.
Read Guide →Learn how REM and deep sleep work, and why waking at the right point in your cycle makes all the difference.
Read Guide →A practical 7-day plan to reset your sleep schedule and wake up feeling refreshed, with science-backed tips.
Read Guide →Based on 90-minute sleep cycles + 14 min to fall asleep
To wake at , fall asleep at:
If you sleep at , wake up at:
We'll add 14 minutes for you to fall asleep
If you sleep now, wake up at:
Sleep occurs in 90-minute cycles. Each includes light sleep, deep sleep, and REM. Waking at the end of a complete cycle — not mid-cycle — is what makes you feel refreshed. Our calculator adds 14 minutes for average sleep onset.
We believe everyone deserves to wake up genuinely rested. SleepCalc makes sleep science simple and accessible — completely free.
To help people improve sleep quality using proven science. Understanding your natural sleep cycles means waking refreshed every morning — without multiple alarms or excessive caffeine.
Millions wake up groggy — not because they slept too little, but because they woke mid-cycle. We built SleepCalc to solve this with science-backed timing that anyone can use.
SleepCalc is and always will be completely free. No registration, no subscription, no credit card. Just enter your time and get instant results — always.
All calculations happen in your browser. We don't store your data, track sleep patterns, or share anything. Your sleep information stays yours.
Human sleep progresses through multiple stages in roughly 90-minute cycles throughout the night. A typical adult needs 4–6 complete cycles. The key insight: waking at the end of a cycle — rather than during deep sleep — determines how refreshed you feel.
Each cycle includes Light Sleep (N1, N2), Deep Sleep (N3/slow-wave), and REM sleep. Our calculator accounts for the average 14 minutes it takes most people to fall asleep (sleep latency).
Most adults need 5–6 complete cycles (7.5–9 hours). Teens and children need more; older adults sometimes need slightly less. Quality matters as much as quantity.
Have a question or suggestion? We'd love to hear from you. We typically respond within 24 hours.
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hello@sleepcalculations.com
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Last updated: June 2026
Welcome to Sleep Calculations ("we", "our", or "us"). We are committed to protecting your personal information and your right to privacy. This Privacy Policy explains how we collect, use, and safeguard your information when you visit sleepcalculations.com.
We collect minimal information to provide our sleep calculator service:
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Last updated: June 2026
By accessing and using Sleep Calculations (sleepcalculations.com), you accept and agree to be bound by these Terms and Conditions. If you do not agree to these terms, please do not use our website.
Sleep Calculations provides a free online sleep cycle calculator for informational and educational purposes only. You may use this service for personal, non-commercial purposes subject to these terms.
The sleep calculations and information provided on this website are for general informational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding sleep disorders or other medical conditions.
While we strive to provide accurate sleep cycle calculations based on established sleep science, we make no guarantees about the accuracy, completeness, or suitability of the information provided. Individual sleep needs may vary.
All content on Sleep Calculations, including text, graphics, logos, and code, is the property of Sleep Calculations and is protected by applicable copyright laws. You may not reproduce, distribute, or create derivative works without our express written permission.
Our website may display advertisements served by Google AdSense and other advertising partners. We are not responsible for the content of these advertisements.
Sleep Calculations shall not be liable for any direct, indirect, incidental, or consequential damages arising from your use of our service or reliance on information provided on this website.
Our website may contain links to external websites. We are not responsible for the content or privacy practices of those sites.
We reserve the right to modify these Terms at any time. Continued use of the website after changes constitutes your acceptance of the new terms.
For questions about these Terms, contact us at: hello@sleepcalculations.com