Sleep Calculator

Find your optimal sleep schedule based on natural sleep cycles

Calculate Bedtime

When do you want to wake up?

Calculate Wake Up Time

When do you want to go to bed?

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How This Sleep Calculator Works

This sleep time calculator uses natural sleep cycles of about 90 minutes. Waking at the end of a cycle can reduce sleep inertia and help you feel more refreshed. Choose a desired wake up time to see recommended bedtimes, or select a bedtime to see your optimal wake up times.

Want to learn more? Read about sleep cycles, sleep hygiene, and sleep disorders.

Recommended Sleep Hours

  • Adults (18-64): 7-9 hours (≈ 5-6 cycles)
  • Older adults (65+): 7-8 hours
  • Teenagers (14-17): 8-10 hours

Everyone is different. Use this bedtime calculator as a guide and adjust based on how you feel.

Sleep Calculator FAQs

Most adults do well with 4-6 cycles per night (about 6-9 hours).

Yes. Waking between cycles (not from deep sleep) can reduce grogginess.

The ideal range is 7-9 hours, though individual needs vary.

Choose a wake up time to get bedtimes, or pick a bedtime to get recommended wake up times based on 90-minute cycles.

A power nap of 10–20 minutes can boost alertness. A full sleep cycle nap of ~90 minutes may aid memory and recovery without heavy sleep inertia.

Sleep latency is the time it takes to fall asleep. Accounting for it helps you select a bedtime so you still wake at the end of a 90-minute cycle. Many people assume zero latency, which can shift the wake up time.

A little extra sleep may reduce sleep debt, but big schedule swings can disrupt the circadian rhythm. Aim for consistency and gradually shift your sleep schedule if needed.

How to Improve Your Sleep Quality

High-quality sleep depends on consistent sleep schedules, a dark and cool sleep environment, and healthy sleep hygiene habits. Go to bed and wake up at the same time daily to reinforce your circadian rhythm. Avoid caffeine and heavy meals late in the day, and reduce exposure to blue light in the evening. Create a relaxing pre-sleep routine—reading, light stretching, or meditation—to signal to your body that it's time to wind down.

If you're looking to build better habits, explore our sleep hygiene guide for practical tips and strategies that support deeper, more restorative sleep.

What Happens During Sleep

Sleep is composed of NREM (stages N1, N2, N3) and REM sleep, cycling every ~90 minutes. In N3 (deep sleep), the body focuses on physical recovery: tissue repair, immune support, and growth hormone release. In REM sleep, the brain consolidates memories, processes emotions, and supports learning and creativity. Cycling between these stages is normal and healthy.

Our sleep cycle article explains how your body moves through these stages and why timing your wake-up at the end of a cycle can help you feel more alert in the morning.

What is REM Sleep?

REM (Rapid Eye Movement) sleep is the stage associated with vivid dreams and heightened brain activity. It supports memory consolidation, emotional regulation, and neuroplasticity. Adults typically spend 20–25% of the night in REM, with longer REM periods occurring in the second half of the night. Disruptions to REM—like inconsistent bedtimes, alcohol, or stress—can affect mood, cognition, and next-day performance.

Learn more about habits that protect REM sleep and overall sleep quality.

Tips to Fall Asleep Faster

  • Keep a consistent bedtime and wake time—even on weekends.
  • Dim lights 60–90 minutes before bed to support melatonin release.
  • Avoid caffeine after mid-day and limit late-night heavy meals.
  • Use a wind-down routine (reading, breathing exercises, light stretching).
  • Keep your bedroom cool, dark, and quiet; consider blackout curtains and white noise.
  • Reserve the bed for sleep and intimacy; avoid doomscrolling in bed.

Common Sleep Questions

How many hours of sleep do I need? Most adults need 7–9 hours per night, often corresponding to 5–6 sleep cycles. Teens and older adults have different ranges. If you wake groggy, try adjusting your sleep window by 15–30 minutes and aim to wake at the end of a 90-minute cycle.

What’s the best time to sleep? Align sleep with your circadian rhythm by keeping a consistent schedule. Use this bedtime calculator to find an optimal window based on your desired wake time or current bedtime.

Explore more in our Learn About Sleep hub and sleep blog for in-depth guides.

How This Sleep Calculator Compares

Unlike a generic sleep chart or simple sleep tracker, this calculator uses 90-minute sleep cycle modeling to recommend precise bedtimes and wake up times. It also accounts for sleep latency (the minutes it takes to fall asleep) by suggesting multiple options across cycles, improving your chances of waking at the end of a REM or light sleep stage.

For deeper learning, explore sleep cycles and our blog guides on sleep debt, napping, and chronotypes.

Benefits of Using a Sleep Cycle Calculator

  • Reduce morning sleep inertia and grogginess by timing wake-ups.
  • Build a consistent sleep schedule aligned to your circadian rhythm.
  • Estimate ideal nap durations and power nap windows.
  • Understand how REM and deep sleep contribute to recovery and cognition.
  • Spot patterns in sleep deprivation or sleep debt and adjust habits.

Tips for Better Sleep

Create a Sleep Routine

Go to bed and wake up at the same time every day, even on weekends.

Limit Screen Time

Avoid screens at least 1 hour before bedtime to improve sleep quality.

Watch Your Caffeine

Avoid caffeine after 2 PM to prevent sleep disruption.

Optimize Your Environment

Keep your bedroom cool, dark, and quiet for better sleep.