How much sleep do you need? Recommended hours by age
This article is general information, not medical advice. It is not a substitute for a doctor, dietitian or other qualified professional who knows your circumstances. If you have a medical condition, are pregnant, or are changing your diet or exercise significantly, talk to one first.
Most adults need 7 to 9 hours of sleep a night. Teenagers need more, around 8 to 10 hours, and younger children more again. Within those ranges people differ, and the best evidence of whether you are getting enough is how you feel and function during the day. The sleep calculator helps time bedtimes and alarms around sleep cycles; this guide covers the recommended amounts and how to find your own.
How much sleep adults need
The NHS says adults need 7 to 9 hours on average. American sleep medicine groups put the adult recommendation at 7 hours or more, and other expert panels suggest 7 to 8 hours for people over 65. Regularly sleeping less than 7 hours is linked in research to poorer concentration and mood, more accidents, weight gain, and higher risks of conditions such as type 2 diabetes, high blood pressure and heart disease. Very few people genuinely function well on less than 6 hours long term, even if they feel used to it.
Sleep needs by age
Recommended hours in 24 hours, including naps for young children, from the American Academy of Sleep Medicine guidance endorsed by paediatric groups:
- Infants, 4 to 12 months: 12 to 16 hours.
- Toddlers, 1 to 2 years: 11 to 14 hours.
- Preschool, 3 to 5 years: 10 to 13 hours.
- School age, 6 to 12 years: 9 to 12 hours.
- Teenagers, 13 to 18 years: 8 to 10 hours.
- Adults: 7 hours or more, commonly given as 7 to 9.
The NHS gives similar broad figures: 9 to 13 hours for children and 12 to 17 hours for toddlers and babies. Teenagers are a special case: their body clocks naturally shift later, which makes early school starts hard and short sleep common.
Finding your own number
Your personal need sits somewhere in the range and is partly genetic. A practical way to find it is to notice how much you sleep when you have no alarm for a week or more, such as on holiday, after the first few nights of catching up. Signs you are not getting enough include needing an alarm to wake every day, relying on caffeine to get through the morning, feeling drowsy in meetings or as a passenger, and sleeping much longer at weekends. Count the hours you are actually asleep, not the time in bed. If you have been running short, the sleep debt calculator adds up the gap over a week, and Sleep debt explained: how it builds up and how to recover explains how to recover.
Timing, cycles and quality
Sleep runs in cycles of roughly 90 minutes, moving through light sleep, deep sleep and REM sleep, with more deep sleep early in the night and more REM towards the morning. Real cycles vary between about 80 and 110 minutes. Waking at the end of a cycle often feels easier than waking from deep sleep. The sleep calculator counts back from your wake-up time in 90-minute cycles and adds 15 minutes to fall asleep, so for a 7:00 am alarm it suggests 9:45 pm for six cycles or 11:15 pm for five. It marks five or six cycles, 7.5 to 9 hours, as the adult target. Total sleep still matters more than hitting a cycle boundary exactly; Sleep cycles, and waking up less awful covers the stages.
Habits that help
- Keep a regular bedtime and wake time, including at weekends where you can.
- Get daylight in the morning and keep evenings dimmer.
- Avoid caffeine for at least six hours before bed, as the NHS advises; the caffeine calculator shows how long a coffee lingers.
- Avoid alcohol and large meals late at night, and leave a few hours between hard exercise and bedtime.
- Keep the bedroom quiet, dark and cool, and put screens away before bed.
- If you cannot sleep, get up and do something calm until you feel sleepy, rather than lying awake.
When to see a doctor
See a GP if poor sleep is affecting your daily life, or if trouble sleeping has lasted three months or more, which the NHS describes as long-term insomnia. Also seek advice if you snore loudly, make gasping or choking noises, or someone sees your breathing stop and start during sleep, which can be signs of sleep apnoea, or if you sleep enough hours but still feel exhausted. A calculator can help with timing and habits, but it cannot diagnose a sleep disorder.
Sources and further reading
The claims in this guide rest on these references, which were checked when the guide was last updated. Spotted an error? The contact page says how to report it.