This mainly depends on your age.
Babies sleep for about 17 hours each day.
Older children only need 9 or 10 hours each night.
Most adults need around 8 hours sleep each night.
Older people need the same amount of sleep, but will often only have one period of deep sleep during the night, usually in the first 3 or 4 hours. After that, they wake more easily. We also tend to dream less as we get older.
There are also differences between people of the same age. Most of us need 8 hours a night, but some (a few) people will get by with only 3 hours a night.
The short periods of being awake can feel much longer than they really are. So you can easily feel that you are not sleeping as much as you are.
What if I don't sleep?
It's easy to worry when you can't sleep. The occasional night without sleep will make you feel tired the next day, but it won't harm your physical or mental health.
However, after several sleepless nights, you will start to find that:
you are tired all the time
you find it difficult to concentrate
you find it hard to make decisions
you start to feel depressed.
This can be very dangerous if you are driving or operating heavy machinery. Many deaths are caused each year by people falling asleep at the wheel while driving.
Lack of sleep can make you more likely to get high blood pressure, diabetes and be overweight. Sleep problems in adult life
Sleeping too little (Insomnia)
You may feel that you aren't getting enough sleep or that, even if you do get the hours, you just aren't getting a good night's rest.
There are many everyday reasons for not sleeping well:
the bedroom may be too noisy, too hot or too cold
the bed may be uncomfortable or too small
you don't have a regular sleep routine
you partner has a different pattern of sleep from you
you aren't getting enough exercise
you eat too late - and find it hard to get off to sleep
you go to bed hungry - and wake up too early
cigarettes, alcohol and drinks containing caffeine, such as tea and coffee
illness, pain or a high temperature.
More serious reasons include:
difficulties at work
anxiety and worry
depression - you wake very early and can't get back to sleep thinking over and over about problems