Sleep Cycle Calculator

Welcome to the Sleep Cycle Calculator! This tool helps you determine the optimal times to go to sleep and wake up in order to feel refreshed.

How It Works

Our sleep calculator is based on the concept of sleep cycles. A sleep cycle is about 90 minutes long. Waking up in the middle of a sleep cycle can leave you feeling groggy and tired. Waking up in between sleep cycles helps you wake up feeling refreshed and alert.

To use the sleep cycle calculator, you input:

  • Your average sleep cycle length (typically 90 minutes)
  • How long it takes you to fall asleep (10-30 minutes for most people)
  • What time you need or want to wake up

The calculator will then tell you what time is optimal for you to go to bed to wake up refreshed right between sleep cycles.

Using the Sleep Cycle Calculator

To use the sleep cycle calculator:

  1. Enter your average sleep cycle length. The default is 90 minutes.
  2. Enter how long it takes you to fall asleep on average. The default is 15 minutes.
  3. Enter the time you need or want to wake up.
  4. Click “Calculate”

The calculator will calculate the best time for you to go to bed and provide a brief explanation of the results.

You can adjust the sleep cycle length and sleep latency inputs to customize the results for your personal sleep habits.

Frequently Asked Questions

How do I figure out my personal sleep cycle length?

The average sleep cycle length is 90 minutes, but it can vary by about 20 minutes in either direction. To determine your personal sleep cycle length, count the number of hours you sleep on a typical night and divide by the number of times you wake up. For example, if you sleep 8 hours and wake up 4 times, your sleep cycle is likely around 2 hours (8/4 = 2).

Why does it take me longer to fall asleep than average?

Factors like stress, underlying medical issues, medications, environment, and diet can affect how quickly you fall asleep. If it takes you longer than 30 minutes to fall asleep on average, speak with your doctor.

What if I don’t have a set wake up time?

If your wake up time changes day to day, enter your earliest possible wake up time into the calculator. This will give you a bedtime that optimizes sleep cycles for that early wake up time. You can still wake up later in your sleep cycle and feel relatively refreshed.

What if I don’t wake up between sleep cycles?

Don’t worry if you wake up in the middle of a sleep cycle. You can still start your day refreshed by giving yourself some time to fully wake up before any important activities. Do some light stretching, make coffee, read the news etc. This will help you feel alert.

How accurate is the calculator?

This calculator provides an estimate based on average sleep cycles. Individual needs vary. Try using the calculator for a week and adjust the inputs as needed to customize it for your personal sleep needs.


Using a sleep cycle calculator can help you optimize your sleep schedule so you wake up feeling energized. By understanding your personal sleep cycles and planning bedtime accordingly, you can start each day refreshed and ready to take on any challenges.

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