Sleep Cycle Calculator: Powered by Sleepytime

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Formerly known as the Sleepytime Calculator, this tool helps get bedtime and wake up times just right.

You should try to fall asleep at one of the following times:

Please keep in mind that you should be falling asleep at these times. The average human takes fourteen minutes to fall asleep, so plan accordingly!

If you head to bed right now, you should try to wake up at one of the following times:

Please keep in mind that you should be falling asleep at these times. The average human takes fourteen minutes to fall asleep, so plan accordingly!

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I want to wake up at...

Sleep Calculator: What Time Should I Go To Bed?

Using the sleep calculator, you can easily tell it when you want to wake up and it will show you a variety of times to fall asleep and how many sleep cycles you will achieve. Keep scrolling for our wake calculator!

You should try to wake up at one of the following times:

Please keep in mind that you should be waking up at these times. The average human takes fourteen minutes to wake up, so plan accordingly!

If you head to bed right now, you should try to wake up at one of the following times:

Please keep in mind that you should be waking up at these times. The average human takes fourteen minutes to wake up, so plan accordingly!

Sleepopolis Moon and Stars

I plan to fall asleep at...

Wake Calculator: What Time Should I Wake Up?

If you know what time you are falling asleep, and want to know the best time to wake up, look no further! Simply add your bedtime into the wake calculator, and it will give you several options for a wake up time and tell you how many sleep cycles you will achieve. 

How Can I Optimize My Sleep Cycle?

“Get 7-8 hours of sleep per night!” This recommendation is pounded into our heads day after day, night after night. While getting a certain number of hours of shut-eye is indeed important, normal sleep goes far beyond just clocking in and out. Instead, it’s characterized by length, quality, and timing, along with the absence of disturbances and disorders. (1)

Let’s take a step back to explain what a sleep cycle actually is, along with what happens when our heads hit the hay at night. It turns out we don’t just fall asleep and wake up eight hours later, with no critical happenings charging through our system (how we wish it were that simple). Instead, our bodies go through a series of waves, called sleep cycles. There are five cycles in total, each lasting around 90 minutes.

The first four stages comprise our non-rapid eye movement (NREM) sleep, while the fifth stage is when we move into rapid eye movement (REM) sleep. Let’s look a little bit more closely at each one.

NREM sleep: This is more than just our eyes staying still. However, the name does hint at the importance of NREM. These four stages are building up intensity towards our REM sleep. Across them, the body moves from really light sleep (Stage 1) to a super deep sleep (Stage 4). By stage 4, it will be really hard to wake someone up. (2) Here’s a little bit more about each stage:

  • Stage 1 is considered the “transitional phase,” when we’re drifting in and out of consciousness
  • Stage 2 is the “light phase,” which is when our heart rate slows down and our core body temperature decreases
  • Stage 3 is “slow wave sleep.” Here, blood pressure drops, heart rate further slows, and our breathing becomes slower and more rhythmic
  • Stage 4 is “deep sleep,” a stage that doesn’t want to be disrupted. Your blood pressure, heart rate, and breathing are all very low.

REM sleep: At the end of our cycle, we actually enter a light stage of sleep. This is when, as the name suggests, our eyes dart up and down and all around, and is most likely when dreaming occurs. Blood pressure, heart rate, and breathing all begin to increase

  • Even though this stage is the most similar to being awake, it’s the furthest point from wakefulness in terms of the sleep cycle. It’s important to remember that we don’t go from being awake to being in REM sleep; rather, we must pass through all the stages of NREM first.

Which brings us to how we actually move through the sleep cycle! It’s important to note that each cycle isn’t, well, cyclical. Instead, we move from being awake, to stage one, two, three, four, and then three, two, one, before going into REM sleep! This cycle, which we like to think of as more of a “wave,” repeats over the course of the night. (3) Many scientists recommend going through 4-6 of these waves, which would provide six to nine hours of shut-eye (remember, each cycle is roughly 90-minutes long). (4) This is why the length of sleep is not what causes us to feel refreshed when we wake up. Rather, the key factor is the number of sleep cycles we complete. The difference between six hours and six hours 30 minutes can be huge; you don’t want to wake up in the middle of a cycle.

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When to Wake Up: How Much Sleep Do I Need?

As we journey through our own cycle of life, our bodies change, and we need different amounts of slumber. (5) Here’s a rough range of how much sleep we need depending on what stage of life we’re in, so you can use the sleep calculator based on age: (6)

  • Newborns: 14-17 hours
  • Infants: 12-15 hours
  • Toddlers: 11-14 hours
  • Pre-Schoolers: 10-13 hours
  • School-Aged Children: 9-11 hours
  • Teenagers: 8-10 hours
  • Young Adults: 7-9 hours
  • Adults: 7-9 hours
  • Older Adults (65+): 7-8 hours

Given these stats, our sleep calculator is best for adults who need up to nine hours of Zzz’s. We’re also working on a sleep calculator age for kids and teenagers since the algorithm is a bit different due to their varying sleep needs. Keep your eyes peeled for that!

The Effects of Sleep Deprivation on Your Body

Insufficient rest can have a significant impact on your well-being. Not only can it impair your physical health, but it can also affect your emotional and cognitive health. One of the primary effects of inadequate shuteye is daytime fatigue. Furthermore, feeling too tired during the day increases your chances of getting into an accident. According to Johns Hopkins Medicine [4], 6,000 fatal car crashes each year are due to drowsy driving. Other physical ramifications include an increased risk of illness, heart disease, high blood pressure, obesity, colorectal cancer, and type 2 diabetes. Poor rest is also linked to an increased of dementia, negative moods, and difficulty concentrating.

Why Is Calculating Our Sleep Important?

It might seem counterintuitive, but it’s very possible to sleep for less time and feel more awake. That’s because it’s better to move through four full cycles (six hours of sleep) versus getting eight hours but waking up in the middle of REM sleep.

So while duration is indeed important — a 90-minute siesta per night probably won’t cut it — the number of complete sleep cycles we go through could trump the number of hours we’re getting.

All in all, calculating our sleep cycles might just be the missing link to our overall health. Optimizing our Zzz’s and better understanding when to hit the hay and when to wake up could add tremendous value to our lives, providing us with more energy, reducing the risk of chronic illnesses like cardiovascular disease and diabetes, combatting weight gain, and even improving our longevity. (7)(8) And who wouldn’t want to calculate their own sleep in order to live a longer and more energized life?

If you find yourself asking “does sleep calculator work for me?” there’s only one way to find out, and luckily there’s a lot of science to back up the role timing can play in our overall sleep health. Give it a whirl, and let us know how it works for you! And while the sleep calculator app will also answer “how long did I sleep?” remember that this data might not matter as much as figuring out if you fulfilled all of your sleep cycles!

How to Improve Your Sleep Quality

If you feel like your slumber is subpar, you can do things to promote better rest. The first tip is to maintain a consistent bedtime and wake-up time, including weekends. The great news is you can use the calculator to help determine your ideal schedule and then stick to that. Secondly, avoid alcohol, caffeine, and nicotine as they can disrupt your rest. Furthermore, going to bed full or hungry can also affect your rest. If you take naps, don’t doze off too late in the day or for more than 30 minutes. Physical activity should also help you rest better, so consider going out for a run or walk if you need an afternoon recharge. Make sure your bedroom is conducive to quality rest by keeping it cool, quiet, and dark. We also recommend taking a look at your sleep products, such as your mattress, pillow, and bedding, to be sure they are helping you get your best sleep. Every person has different things to consider when shopping for a mattress, pillow, or other sleep accessories. For instance, if you are a side sleeper, you will need a mattress that provides pressure relief to your shoulders and hips to prevent joint pain, which usually means a mattress that incorporates soft, contouring materials like memory foam or a pillow top. Or if you are a stomach sleeper, you should opt for a mattress that’s firmer to support your hips and maintain proper spinal alignment, in order to prevent back pain. Lastly, help alleviate stress that can keep you up by establishing a relaxing nightly routine before bed, such as reading a book or drinking hot tea. Read more on how to improve your sleep hygiene in our full guide.

How many hours of sleep is recommended?

Although the calculator can help you wake up during a lighter slumber, that’s not to say you should actively pursue fewer hours of shuteye than recommended by the medical community. Experts suggest that adults get between 7 and 9 [5] hours of slumber each night, which correlates to 5 or 6 full cycles. However, this amount can vary depending on your health and personal circumstances. For instance, if you are recovering from a cold, you will likely doze off longer than you would normally. Babies, children, and teens should get even more slumber. For example, a newborn baby needs between 14 and 17 hours of shuteye.

Is it normal to still feel tired after sleeping for 8 hours?

Yes, you can sleep for 8 hours and still feel tired. Even though you got the amount of rest that health experts recommend, you likely woke up toward the end of a sleep cycle. The length of these cycles can vary. We mentioned earlier that a complete cycle could last from 90 to 110 minutes. The duration of each stage can vary too, further affecting the cycle duration. Each person is different, and therefore, you cannot count down a cycle to the exact minute. Instead, these numbers represent a general observation from health experts to help people better understand how we rest.


    1. Medic G et al. Short- and long-term health consequences of sleep disruption. Nat Sci Sleep. 2017 May; 9: 151–161.
    2. Purves D et al. Stages of Sleep Neuroscience. 2nd edition. 2001
    3. Merica H et al. Internal structure of sleep cycles in a healthy population. Sleep. 1986 Dec;9(4):502-13.
    4. Cologne, G et al. What is “normal” sleep? Informed Health Online. 2016 Dec
    5. Ferrara M et al. How much sleep do we need? Sleep Med Rev. 2001 Apr;5(2):155-179.
    6. How much sleep do we really need?,
    7. Torbjörn Åkerstedt et al. Sleep duration, mortality and the influence of age. Eur J Epidemiol. 2017; 32(10): 881–891.
    8. Alvarez GG. The impact of daily sleep duration on health: a review of the literature. Prog Cardiovasc Nurs. 2004 Spring;19(2):56-9

Sleepopolis Team

The Sleepopolis team is all about helping you sleep better. We live, eat, breathe, and sleep (ha!) all things, well, sleep! Whether you need a new mattress, are having trouble sleeping, or are just tired of counting sheep, we've got you covered. Check back here often for the latest and greatest in mattress reviews, sleep news, or health tips, and in the meantime, sleep well.