Sleep Cycle Calculator

Wake up refreshed by timing your sleep in 90-minute cycles.

How It Works

Sleep occurs in cycles of approximately 90 minutes. Each cycle includes light sleep, deep sleep, and REM sleep. Waking up between cycles feels natural and refreshed. Waking up mid-cycle leaves you groggy and disoriented.

Pro tip: Factor in 15 minutes to fall asleep when choosing your bedtime.

I want to wake up at:

💤 Recommended Bedtimes

Assuming 15 minutes to fall asleep

Understanding the Results

Each recommended bedtime gives you a complete number of sleep cycles. Most adults need 5-6 cycles (7.5-9 hours) for optimal rest.

4 cycles (6 hours): Minimum for basic function—not sustainable long-term
5 cycles (7.5 hours): Good for most adults
6 cycles (9 hours): Ideal for athletes, young adults, or recovery periods

Remember: Consistency matters more than perfection. Stick to the same schedule even on weekends.