How Much Sleep Do Teenagers Need? Hours, Body Clocks and School

If you've ever wondered how much sleep teenagers need, the answer is more than most of them get. Australian guidance puts it at 8 to 10 hours a night, and the problem isn't laziness: a teenager's body clock genuinely shifts later during puberty, right when school demands an early start. This guide covers the recommended hours, why teenagers can't fall asleep early or wake up in the morning, what the evidence says about school start times, and what parents can actually do.

The short answer: teenagers need 8 to 10 hours of sleep a night, with some needing as little as 7 or as much as 11. Most get less, because melatonin is released later in adolescence, so they don't feel sleepy until late, yet school still starts early. You can't move their biology, but you can protect it: a steady wake time within one to two hours all week, screens out of the bedroom at night, morning daylight, no caffeine late in the day, and an alarm they own. If sleep problems are affecting school, mood or health, see your GP.

How much sleep do teenagers need?

The Raising Children Network says most teenagers need 8 to 10 hours of sleep each night, and that some need as little as 7 hours or as much as 11 (source). The Sleep Health Foundation gives the same range, and adds that most teenagers around the world get between 7 and 8 hours, so many are running a sleep debt (source).

Age	Sleep needed per night	Source
5 to 11 years	9 to 11 hours	Raising Children Network
Teenagers	8 to 10 hours	Raising Children Network, Sleep Health Foundation
Some teenagers	As little as 7 or as much as 11 hours	Raising Children Network

A rough check: a teenager who has to be up at 6.45am needs to be asleep (not in bed, asleep) by about 10.45pm for eight hours, and by 8.45pm for ten.

Why teenagers can't fall asleep or wake up

• Later melatonin. Raising Children explains that in the early teen years, children start to secrete melatonin later at night than they did in childhood, which shifts their circadian rhythm, and that as the brain matures during puberty they can stay awake longer (source). The Sleep Health Foundation says the same: melatonin release is delayed, so teenagers aren't tired until later in the evening.
• Early school. A later body clock meeting a 7am alarm means a teenager is being woken in what is, for them, the middle of the night. That's why the wake-up is so brutal and the grogginess lasts. See what is sleep inertia?
• Weekend catch-up. Raising Children notes that late bedtimes plus early school wake-ups leave many teens short of sleep in the week, so they sleep in on weekends. The sleep-in pushes the body clock later again, and Monday is worse. This is social jet lag.
• Screens, caffeine and stress. Each adds to the biology rather than causing it.

What a lack of sleep does

Raising Children says lack of sleep makes it harder for teenagers to regulate emotions, pay attention, do well at school and get along with others, and that being tired all the time can contribute to anxiety and depression (source). The Sleep Health Foundation lists signs that a teenager is struggling: often late for school, sleepy during the day, moody or grumpy, and grades slipping (source).

School start times

Most Australian high schools start between 8.30 and 9am (source). That's later than many US schools, and the difference shows in the data. A study comparing South Australian and Rhode Island teenagers found that the Australian schools started between about 8.20 and 9am while the US schools started around 7.45am, and that Australian adolescents got an average of 47 minutes more sleep per school night, with school start time having the largest effect on sleep duration (source).

The same study found something parents can use directly: teenagers whose parents set a bedtime gained about 24 minutes of sleep a night.

A few Australian schools have tried later starts for senior students. The ABC reported that Adelaide High School moved Years 11 and 12 to a 9.20am start, and that Flinders University sleep researcher Associate Professor Jessica Paterson suggested a start no earlier than 9am suits teenage body clocks (source).

What parents can do

Raising Children's advice is that teenagers need to be involved in solving their own sleep problems: ask what makes it hard to sleep, let them choose a habit to try, and praise the effort (source). The habits it recommends:

1. A steady wake time. Keep school-day and weekend wake-ups within one to two hours of each other. The most effective lever and the least popular. See fixed wake-up time.
2. Get out of bed on waking rather than lying there.
3. Screens off an hour before lights out, and devices charged in a family room overnight, not the bedroom.
4. Morning daylight. Open the blinds, eat breakfast near a window, walk part of the way to school. Light in the morning helps suppress melatonin then and release it in the evening.
5. No caffeine late in the day. Energy drinks, coffee, tea, cola and chocolate all count.
6. Naps no longer than 20 minutes, early afternoon only.
7. A wind-down hour: shower, reading, music, no homework in bed.

For a teenager whose body clock has drifted very late, the Sleep Health Foundation suggests a gradual fix: move bedtime and wake time earlier by about 30 minutes at a time, and limit weekend sleep-ins to under two hours (source).

The alarm question

Many families end up with the parent as the alarm: three trips upstairs, rising volume, a bad start for everyone. It's worth handing the job back.

• Their own alarm, not yours. If the phone is out of the bedroom, the alarm can't be the phone, which is the point.
• One they can't easily tune out. Teenagers sleep deeply and will sleep through a 30-second ringtone. An alarm that builds in strength, worn or placed so they can't ignore it, works better. See alarms for teenagers who sleep through alarms.
• Light as the second alarm. Blinds up and the light on when the alarm goes.

When to see your GP

This guide is general information, not medical advice. Raising Children says a change in sleep behaviour, such as going to bed later than you'd like, isn't necessarily a problem, but if persistent sleep problems are affecting your teenager's wellbeing, schoolwork, relationships or mental health, it's time to see a GP, school counsellor, psychologist or sleep specialist (source). Also see a GP if your teenager snores loudly, is exhausted despite long nights, or if low mood or anxiety is part of the picture.

Where the Sovune Nudge fits

We make the Sovune Nudge, a vibrating alarm wristband, so we're not neutral. For a teenager, it's an alarm that lives on their wrist rather than on a phone, and that they feel rather than hear.

• Wakes with vibration on the wrist, starting as a gentle tap and building through three intensity levels over a full minute. It can be switched off sooner.
• No app, no phone, no Bluetooth. Set on the band itself, so it works with a phone-free bedroom.
• Silent, so an early-rising teenager doesn't wake a sibling in the next room.
• Three alarms, for school days, sport mornings and a backup.
• Up to 14 days of nightly use per charge, so a forgotten charge doesn't mean a missed morning.

It comes with a 30-day money-back guarantee.

Quick answers

How much sleep does a 15-year-old need? 8 to 10 hours a night, according to the Raising Children Network and the Sleep Health Foundation. Some need as little as 7 or as much as 11.

Why is my teenager so hard to wake up? Their body clock shifts later in puberty, so a 7am alarm lands in their biological night. Short sleep makes it worse.

Should I let my teenager sleep in on weekends? A bit. Keeping wake times within one to two hours of school days protects the body clock; longer sleep-ins make Monday harder.

Do later school start times help? The evidence says yes. In one Australian-US comparison, later-starting Australian students got about 47 minutes more sleep per school night.

For every type of silent alarm compared, see our complete guide to vibrating alarms in Australia.

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