What time should a 15 year old go to bed?

Last reviewed: 14 September 2026

Fifteen is the GCSE year, and the year sleep is most often traded for revision. The research on whether that trade works is unusually clear, and it does not favour the late night.

Bedtime chart for a 15-year-old

Find the time your teenager has to be up, and read across. These bedtimes are lights out, not the start of the evening — they already include about 15 minutes to fall asleep, which is a typical figure at this age.

If your 15-year-old wakes on their own at roughly the right time and is cheerful for the first twenty minutes of the day, the bedtime you are using is working. If they need waking every morning, it is too late — whatever the chart says.

How much sleep does a 15-year-old need?

A 15-year-old needs 8 to 10 hours of sleep a night. The major guidelines agree closely, and all of them give a range rather than a number because healthy teenagers genuinely vary by an hour or more either side.

Sleep and revision: what the evidence actually shows

The intuition is that you can borrow an hour from sleep and spend it on revision. The research points firmly the other way, and one finding in particular is worth knowing.

A study tracking students' sleep across a whole semester found that sleep duration, quality and consistency together accounted for roughly a quarter of the variation in grades. The striking part was when the sleep mattered: sleep in the month and the week before a test predicted performance, while sleep on the night before showed no significant correlation at all.

The mechanism is not mysterious. Newly learned material is consolidated into durable memory during sleep — slow-wave sleep and REM both play a part, and REM is concentrated in the last cycles of the night, exactly the ones a late finish removes. Revising and then sleeping short is close to revising and then deliberately discarding part of it.

Exam-season insomnia

Stress-driven sleeplessness is common at fifteen and it has its own logic: lying in bed unable to sleep creates an association between the bed and anxiety, which makes the next night harder. Two things help more than anything else. First, stop revising at least an hour before bed — a brain that was working at 10:55 PM is not going to be asleep at 11:00 PM. Second, if they have been awake for twenty minutes or more, get up, do something dull in dim light, and go back when sleepy, so the bed does not become the place where they fail to sleep.

The revision timetable that protects sleep

A fixed finishing time is worth more than a fixed number of hours. Setting a hard stop at 9:00 or 9:30 PM tends to make the earlier hours more productive, because the work has a deadline; an open-ended evening expands to fill itself and ends at midnight having achieved less.

Signs a 15-year-old is not getting enough sleep

Tiredness at this age rarely announces itself as tiredness. It shows up as mood, motivation and concentration, and the pattern across the week is the giveaway — worse by Thursday, better after a weekend.

• revising past 11:00 PM most nights
• sleeping until midday or later at weekends
• relying on energy drinks or coffee to revise
• rising anxiety, tearfulness or irritability through the spring term
• reading the same page repeatedly without it going in — a classic marker of a sleep-deprived working memory

Snoring every night, long pauses in breathing, or persistent mouth-breathing during sleep are different — those are worth raising with your GP rather than treating as a bedtime problem.

Evening habits that work at fifteen

At fifteen the useful structure is a set of agreements rather than a routine: revision has a finishing time, the phone charges outside the bedroom, the lights go down after nine, and the wake-up time holds within about an hour at weekends.

The argument that lands at this age is almost never health. It is performance — and it happens to be true. Framing sleep as part of the revision strategy rather than as a rival to it is both more accurate and considerably more persuasive than anything about wellbeing.

How to move bedtime earlier without a fight

1. Fix the wake-up time first. Same time every day, weekends included, for a week. A stable morning anchors the body clock far more effectively than a stable bedtime does.
2. Move in 15-minute steps. Shift lights out 15 minutes earlier every three or four nights. The body clock will follow that; it will fight an hour.
3. Get daylight into the morning. Curtains open on waking, and ten to fifteen minutes outside before school if you can manage it.
4. End screens before the wind-down starts, not as part of it — stopping something engaging is itself stimulating.
5. Give it a fortnight. Two or three nights tells you nothing. Judge it by how the mornings look after two weeks.