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Sleep Time Calculator

Created by Gabriela Diaz
Reviewed by Steven Wooding
Based on research by
Hirshkowitz M, Whiton K, Albert SM, Alessi C, Bruni O, DonCarlos L, Hazen N, Herman J, Katz ES, Kheirandish-Gozal L, Neubauer DN, O'Donnell AE, Ohayon M, Peever J, Rawding R, Sachdeva RC, Setters B, Vitiello MV, Ware JC, Adams Hillard PJ. National Sleep Foundation's sleep time duration recommendations: methodology and results summary.; Sleep Health; March 2015See 1 more source
Shen, X., Wu, Y. & Zhang, D. Nighttime sleep duration, 24-hour sleep duration and risk of all-cause mortality among adults: a meta-analysis of prospective cohort studies; Scientific Reports; February 2016
Last updated: Jan 18, 2024

With this sleep time calculator, you can find out what time you should go to bed to wake up at a given time with complete sleep cycles, so you can wake up all fresh and ready to tackle the day.

If you ever wonder why some days you wake up fresh and energized while some other days you need a cup of coffee to open your eyes, most likely, the answer is related to your sleep time 💤

Keep reading and find out:

  • What is sleep time?
  • How much sleep do you need?
  • What time should you go to sleep?
  • How to calculate how much sleep you need.

What's sleep time? – Why is sleep time important?

Sleep time is the number of hours that we use to rest and regenerate the body and mind. This amount of hours is calculated in cycles, and each cycle consists of 90-minute-long sequences repeated throughout the night.

Waking up at the end of a cycle makes you feel fresh and energized, but on those days that you feel like you can’t wake up, you probably woke up in the middle of a cycle.

How much sleep do I need?

Does it happen to you that you are always the first to get up? Or maybe the last one to do so? This is because the number of hours you need is genetic and pre-determined before birth. However, it does vary over your life time (babies and teenagers sleep longer hours).

While some people only need 5 hours of sleep a day, some others need 9 hours. In general, the recommended sleep time is between 7 h and 30 min (5 cycles) and 9 h of sleep (6 cycles).

What time should I go to sleep?

Do you have an important presentation tomorrow and need to be as sharp as possible? Most likely, you are wondering what time you should go to bed to make this happen. To do so:

  1. Consider how many cycles of sleep you need.

  2. Convert the number of cycles into hours, and add 15 minutes (average amount of time it takes to fall asleep) or the amount of time it takes you to fall asleep.

  3. Once you know how much time you need to sleep, you can estimate your bedtime by counting back these hours from your wake-up time. This will help you wake up fresh and sharp ☀

🙋 You can also opt to use our sleep time calculator to make it easier on you!

How to use this sleep time calculator

To have a good night's sleep and wake up fresh and like new, you can use our sleep time calculator:

  1. In the Time to fall asleep field, indicate how long it takes you to fall asleep.

    In general, it takes 10-20 minutes to fall asleep; however, some people fall asleep as soon as they lay down while others toss and turn for hours. Our calculator has 15 minutes as default time.

  2. Select the time you want to get up in the Waking up time section. The calculator has intervals of 15 minutes for this section.

  3. The calculator will display your result. Identify how many sleep cycles you'd like to complete and select the time you need to go to bed.

    Remember that an average person needs between 5-6 cycles every night.

Continue learning about sleep

Here at Omni, we have some other sleep-related tools that you might enjoy:


How do I determine what time I should go to sleep?

To find out your bedtime:

  1. Consider what time you want to wake up. Say 7:00 am.

  2. Decide how many sleep cycles you'd like to complete. Consider 5 cycles.

  3. Express cycles in hours. Remember that 1 cycle = 90 minutes. Then 5 cycles = 7.5 hours.

  4. Starting at your wake time, work back 7.5 hours to find your bedtime. This is 11.30 pm.

  5. Add another 15 minutes to account for the time it takes you to fall asleep. The sleep time in our example would be 11.15 pm.

How much sleep do I need to not feel tired?

An average person needs between 7 h 30 mins (5 cycles) and 9 h (6 cycles) of sleep to feel fresh and energized. However, some people only need 6 h of sleep (4 cycles). The amount of hours of sleep is genetically determined.

Do I need more time of sleep the older I get?

No. Surprisingly, the older we get, the fewer hours of sleep we need. A newborn baby needs more sleep time than a 3 to 5 years old child, who needs more sleep time than an adult, who needs more sleep time than an older adult.

Gabriela Diaz
What time should I go to sleep?
Time to fall asleep
Waking up time
7:00 AM

To wake up at the end of a sleep cycle, go to sleep at:
  - 9:45 PM (6 cycles, 9h of sleep) - recommended for long-sleepers,
  - 11:15 PM (5 cycles, 7h30m of sleep) - recommended for average-sleepers,
  - 12:45 AM (4 cycles, 6h of sleep) - recommended for short-sleepers,
  - 2:15 AM (3 cycles, 4h30m of sleep),
  - 3:45 AM (2 cycles, 3h of sleep),
  - 5:15 AM (1 cycle, 1h30m of sleep).

If you go to sleep NOW, you should wake up at:
  - 11:19 PM (6 cycles, 9h of sleep) - recommended for long-sleepers,
  - 9:49 PM (5 cycles, 7h30m of sleep) - recommended for average-sleepers,
  - 8:19 PM (4 cycles, 6h of sleep) - recommended for short-sleepers,
  - 6:49 PM (3 cycles, 4h30m of sleep),
  - 5:19 PM (2 cycles, 3h of sleep),
  - 3:49 PM (1 cycle, 1h30m of sleep).
Check out 5 similar sleep calculators 😴
AHIEpworth sleepiness scalePediatric Epworth sleepiness scale… 2 more
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