How Much Sleep Do Teenagers Need? Hours, Bedtimes and Why Teens Stay Up Late

Teenagers aged 13 to 18 need 8 to 10 hours of sleep a night, according to the American Academy of Sleep Medicine. That's more than most adults need, and far more than most teens actually get on school nights.

The problem usually isn't laziness or phones alone. Around puberty, a teenager's body clock shifts later, while school still starts early. The result is a squeeze from both ends.

Why teens can't just go to bed earlier

During puberty, the internal clock that tells the body when to feel sleepy moves later in the evening. A 15-year-old may genuinely not feel tired until 10:30 or 11 PM, and asking them to sleep at 9 PM can mean lying awake.

A classic study followed students from 9th grade, when school started at 8:25 AM, into 10th grade, when it started at 7:20 AM. With the earlier start, students woke up earlier but did not fall asleep earlier, so they simply slept less. Their melatonin, the hormone that signals night, also rose later in 10th grade than in 9th. Given a chance to nap at 8:30 AM in the lab, 10th graders fell asleep in about 5 minutes on average.

In other words, the late body clock and the early bell pull in opposite directions, and sleep loses.

What school start times have to do with it

The American Academy of Pediatrics calls insufficient sleep in teens a public health issue. Its policy statement names start times before 8:30 AM as a key, fixable cause, and urges middle and high schools to start late enough for students to get 8.5 to 9.5 hours.

You can't change your school's bell schedule overnight. But it helps to know that a tired teen with a 7:15 AM start isn't failing at sleep. The schedule makes 9 hours very hard.

Bedtime table for common school wake-up times

Each bedtime includes about 15 minutes to fall asleep. The 9-hour column is a good everyday target. The 8-hour column is the latest bedtime that still meets the minimum.

For a very early wake-up, even the 8-hour bedtime may land before a teen feels sleepy. That's where the habits below matter most. For younger kids' bedtimes, see the bedtime chart for kids. For any age or wake time, the sleep needs by age calculator gives the window in a tap.

How to help a teen get more sleep

Because the body clock is the main hurdle, the most useful steps are the ones that nudge it earlier.

• Get bright light soon after waking. Morning daylight is the strongest signal for moving the clock earlier. Open the blinds, eat breakfast by a window, or walk part of the way to school.
• Dim lights and screens in the last hour. Bright light late in the evening pushes the clock later. Charging phones outside the bedroom removes the late-night scroll entirely.
• Keep weekend wake-ups within about 1 to 2 hours of school days. A little extra sleep is fine, but sleeping until noon resets the clock later and makes Monday brutal. More on this in is it bad to sleep in on weekends.
• Watch afternoon caffeine. Energy drinks, iced coffee and some sodas can still be working at bedtime. The caffeine calculator shows how long a drink lingers.
• Move bedtime in 15-minute steps. Jumping from midnight to 9:30 PM rarely works. Shift it every few nights.
• Protect the wind-down. Homework, sports and jobs pile up. A predictable 20 to 30 minute routine before lights-out helps the body expect sleep.

Signs a teen isn't getting enough sleep

• Hard to wake on school days, then sleeping several extra hours on weekends
• Dozing in class, in the car or while watching TV
• Irritability, low mood or trouble concentrating
• Relying on caffeine to get through the morning

Talk to your teen's doctor if they snore loudly or seem to stop breathing in sleep, are very sleepy during the day despite enough time in bed, or have trouble falling or staying asleep for weeks. Drowsy driving is a real risk for newly licensed teens, so take persistent sleepiness seriously.