SleepCalculator
Find ideal bedtimes or wake-up times using typical 90-minute sleep cycles and a ~15 minute fall-asleep buffer.
Recommended times
Click any time to copy it. These account for 15 minutes to fall asleep.
Quick tips
- Aim for 4–6 full cycles (6–9 hours).
- Short naps (~20 min) can boost alertness without sleep inertia.
- Maintain a consistent sleep schedule, even on weekends.
- Avoid caffeine and heavy meals close to bedtime.
- Dim lights and reduce screen time at least 30 min before sleep.
- Keep your bedroom cool, dark, and quiet for better rest.
The Sleep Calculator is designed to help you find the best times to sleep and wake up so that you can feel refreshed and energetic.
It works by using the concept of sleep cycles.
A normal sleep cycle lasts about 90 minutes, and most people need
4 to 6 full cycles each night, which means around 6 to 9 hours of sleep.
Instead of just focusing on how many hours you sleep, this tool calculates the exact times when you should go to bed or wake up. Waking up in the middle of a sleep cycle often makes you feel tired, groggy, or slow. On the other hand, waking up at the end of a cycle helps you feel more awake and refreshed. That’s why the Sleep Calculator doesn’t just count hours—it focuses on the quality of your sleep.
By using this tool, you can plan your bedtime if you already know when you need to wake up, or you can choose a wake-up time based on when you’re going to bed. It also gives quick tips, like the value of short naps and the importance of building a regular sleep routine. Whether you are a student, a busy professional, or just want to improve your daily energy, this tool can guide you toward healthier sleeping habits in a simple and easy way.