How Much Sleep Do You Need? Calculate The Ideal Amount

image showing how much sleep experts recommend you get according to your age

The exact amount of sleep you need is different for each person, and will also change during your life.

But as a general rule of thumb, sleep experts do have some recommendations based on your age alone.

For example, newborns need 14 to 17 hours, teens need 8 to 10 hours, and most adults between 7 and 9 hours.

Many people try to survive on less sleep than the experts recommend. But regularly not getting enough sleep can have long-term health risks.

Equally, we’re all different. So along with the broad expert advice, it’s good to work out how much sleep you personally need to be at your best. And you’ll find out how to do that later in this article.

How much sleep you need according to your age

There are many factors that can affect the amount of sleep you really need, including:

  • Your age.
  • Your health.
  • How physically and mentally active you are.
  • Your diet and other lifestyle choices.
  • Your genetics.

In 2015, the National Sleep Foundation produced new and detailed guidance on the ideal sleep duration for different age groups.

The foundation brought together a team of 18 sleep experts from a range of fields: sleep, physiology, anatomy, gerontology, pediatrics, gynecology and neurology.

They analyzed over 300 research studies to create their guidance. So considering their expertise, this could be the best advice for many years to come.

In addition to the ideal sleep duration, they also included two other recommendations:

  • May be appropriate: These sleep durations might not be ideal, but shouldn’t cause undue concern.
  • Not recommended: These sleep durations are definitely outside of the normal recommended limits.

You can see their conclusions in the table below. It will give you a starting point to work out more accurately how much is right for you.

AgeRecommended
sleep length
May be
appropriate
Not
recommended
Newborn
0-3 Months
14 to 1711 to 13
18 to 19
Less than 11
More than 19
Infants
4-11 Months
12 to 1510 to 11
16 to 18
Less than 10
More than 18
Toddlers
1-2 Years
11 to 149 to 10
15 to 16
Less than 9
More than 16
Pre-school
3-5 Years
10 to 138 to 9
14
Less than 8
More than 14
Children
6-13 Years
9 to 117 to 8
12
Less than 7
More than 12
Teenagers
14-17 Years
8 to 107
11
Less than 7
More than 11
Young adults
16-25 Years
7 to 96
10 to 11
Less than 6
More than 11
Adults
26-64 Years
7 to 96
10
Less than 6
More than 10
Older adults
Over 65
7 to 85 to 6
9
Less than 5
More than 9

Why do some people need much less sleep?

If most adults need 7 to 9 hours, how is that some lucky people seem to manage on just 6 hours, or even less?

The answer might partly lie in the genetics of sleep needs. Unfortunately, it’s thought that only around 3% of people have the gene which lets them survive on little sleep.

So you’re probably in the 97% that need at least 7 hours per night to avoid the long-term consequences of sleep deprivation.

Is too much sleep bad?

Most people worry about not getting enough sleep. However, researchers have found that too much sleep can also be bad for your health.

Too much sleep can be associated with a higher risk of being overweight, diabetes or heart problems.

Work out the right amount of sleep for you personally

The medical guidance based on age isn’t very specific – how do you know if you need 7, 8 or 9 hours?

So it might be useful to work out how much sleep you personally need. And that means considering two questions:

  • How much sleep do you need to survive?
  • How much sleep do you need to function at your best and be happiest?

The answer to these two questions could be quite different. For example, you may think that you can scrape through the day if you’ve had 6 hours sleep.

But is 6 hours enough to work efficiently and be in a good mood all day?

Or does it turn you into a coffee fiend, and make you look forward to going back to bed from the minute you wake up?

Keep a manual sleep diary

image of a woman writing in her diary

An excellent way to work out your optimum sleep time is to keep a sleep diary. In it you should record 4 things each day:

  • The time you fell asleep.
  • The time you woke up.
  • How long you slept for.
  • How you felt the next day.

For the time you went to sleep, try to approximate when you fell asleep, not when you went to bed. It might be difficult if you’re restless in the dark for some time, but try to be as accurate as you can.

Look for patterns in your sleep and daytime functioning

After a couple of weeks, it’s time to analyze your diary for patterns. If you felt alert, energized, and able to do things well all day long, you probably slept enough the night before.

But if you felt any of the symptoms of sleep deprivation (see below), you might not have gotten enough the night or two before.

You can continue doing this for as long as you like. And over the weeks or months, you’ll get a clearer picture of the amount of sleep you need to aim for.

If you want more accurate information over a period of time, you could invest in a good sleep tracker. But it’s still good to keep a manual diary of how you felt each day.

You can find out about how they work, and what options you have, in the sleep tracker review.

Sleep deprivation symptoms to watch out for

It’s possible to experience sleep deprivation without realizing. When you complete your sleep diary, keep an eye out for these signs:

  • Always needing an alarm clock to wake up, or using the snooze function a lot.
  • Finding it difficult to get out of bed in the morning.
  • Feeling sleepy at work, in school or in warm environments.
  • Feeling very tired after a heavy meal, in the afternoons or when driving.
  • Being grumpy or irritable.
  • Having difficulty concentrating, remembering things or making decisions.
  • A change in appetite or weight gain.
  • Being more accident prone.
  • It only takes you a couple of minutes to fall asleep at night.
  • Susceptible to colds and infections.
  • Stressful things are difficult to cope with.
  • Finding it hard to motivate yourself to do normal activities.
  • Your reaction times are reduced.

infographic explaining key sleep deprivation symptoms

There may, of course, be other explanations for some of these. But it’s still important to record them in the context of working out your sleep.

The key is to carefully check your diary to see if you only experience the symptoms on the days after having less sleep.

That will then be a good indicator that you’re not getting enough sleep on those days.

And hopefully, you’ll also start to see how many hours of sleep results in you writing ‘felt good all day’ in your diary!

Don’t panic if you’re not sleeping enough

Even though these guidelines exist, try not to panic if you don’t always get that optimum amount.

For example, if you’ve worked out that your golden number of hours sleep is exactly 8, then the temptation will be to start worrying when you only get 7.

The reality is that most people can function well with less sleep from time to time.

So on the nights when it takes you longer to fall asleep, try not to worry that the next day will be difficult. That thought will only keep you awake longer.

How much do you sleep?

How much sleep do you think you get on average, and how much do you think you need to be at your best? Feel free to leave a comment below.

10 CommentsLeave a comment

  • Hey i am Tarun. I take 6 hours sleep, sometimes it helps to feel cool and energetic, and sometimes i feel lazy, and I don’t feel well. Can you please tell me either i should continue with schedule and need to make some changes?

    • Hi Tarun
      Thanks for your comment. If you think that you sometimes don’t sleep enough and it you’re tired the next day, then yes, maybe you need a little more sleep.
      Regards
      Ethan

  • I’m 16 and I usually get 4 hours of sleep but I can get by on none at all. Is this bad? Also when I do sleep it’s restless and i get nightmares.

    • Hi Grace
      Thanks for your comment. It’s not an ideal amount of sleep, and eventually will probably impact on your daily life, if it hasn’t already. Do you never sleep more than that? Do you know what stops you from sleeping more? Do you feel stressed or anxious about anything?
      Regards
      Ethan

    • @Grace: Not sure if you’re still subscribed to this thread but here goes nothing. I’m a few decades older than you but do remember my teenage years. As a child and teenager I had far more nightmares than I do as an adult. My guess has always been that it related the maturing of the brain. That may be a normal part of ‘growing up’.

      As for getting 4 hours per night, that’s NOT normal. I work with teens, and, while lack of sleep has become a HUGE issue in recent years, 4 hours is abnormal, even by modern teenager standards.

      #1 Go see your family doctor. It is NOT, I repeat NOT normal to be getting 4 hours a sleep. Teenage bodies need far more than that to grow and, especially, for mental health.

      #2 Develop a plan for your devices. If you have one in the room with you at night it is too close. Set up a do not disturb function for the time that you want to be asleep and stick to it. Find a safe spot in your home BUT NOT IN YOUR BEDROOM where you can leave your device(s).

      #3 Don’t watch movies after a certain hour. Period. Full stop. Same goes for being on the internet.

      #4 Consider asking the adult in your life to put a time-based lock on your computer THAT YOU CAN’T UNLOCK for certain hours.

      Since your comment is from three months ago I do hope you’ve resolved your sleep issues, but, having dealt with mine for years, I doubt it (of course, mine appear to be hereditary, and, only partially environmental).

  • I need at least 8 hours of sleep to be fully rested and ready for work/school. However, sometimes when the time gets very busy that includes school + work, I would get only about 5 hours of sleep but then I would feel tired the whole day. On the weekends I love to sleep in for about 10 hours.

    • Hi Weston
      Thanks for your comment. I’m the same – about 8 hours is what makes me at my best I think. I know it’s tough when you sleep for much less than you’d like to; the next day can be difficult to get through. Maybe if you try sleeping for just the normal 8 hours at the weekend too, it might help stabilize your sleep pattern so you get 8 hours more regularly and not the 5 hours.

      Regards
      Ethan

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