Sleep Calculator for Teens
Teenagers need 8 to 10 hours, but biology pushes bedtime later. Enter a school-day wake time to get realistic bedtimes that respect how teen sleep actually works.
Add a wake time to also get suggested bedtimes for this age.
Your recommended sleep range will appear here after you calculate.
How it works
Teenagers aged 13 to 17 are recommended 8 to 10 hours of sleep per night by the expert consensus endorsed by the American Academy of Sleep Medicine. Almost no teen gets that on a school night. The reason is partly structural: during puberty the body clock shifts later, so the wave of sleepiness that used to arrive at 21:00 now arrives closer to 23:00. Telling a teen to simply go to bed earlier fights biology, which is why the wake time matters more than the bedtime lecture.
This calculator works backward from the one fixed point in a teen's week, usually the school alarm. Enter the wake time and you get a bedtime window for 8 to 10 hours, minus about 15 minutes to fall asleep. Treat the window as a target range, not a curfew set in stone. Many families find the realistic win is moving bedtime 15 to 30 minutes earlier every few nights rather than demanding a two-hour jump on Sunday.
The highest-leverage habit is a fixed wake time, seven days a week. Sleeping until noon on Saturday feels like recovery, but it shoves the body clock later and makes Sunday night and Monday morning worse. Keeping weekend wake time within about an hour of the school alarm does more for weekday alertness than any supplement or app. Morning light helps too: daylight in the first hour after waking is the strongest signal that sets the clock.
Screens deserve an honest mention. It is not just the blue light; it is that messaging, games, and feeds keep the brain in an alert, social mode right up to lights-out. A phone charging outside the bedroom removes the decision entirely and works better than any amount of willpower at midnight. Caffeine after midday has a similar hidden cost, delaying the sleepiness signal by hours.
For the general version covering every age, see the sleep needs calculator. To plan around a fixed alarm using full sleep cycles, try the bedtime calculator, and read how much sleep you need by age for the evidence behind these ranges.
These calculators give planning estimates based on average sleep cycle timing. They are not medical advice and cannot diagnose sleep problems. If poor sleep persists, talk to a clinician.
Common questions
How much sleep does a 15 year old need?
8 to 10 hours per night, per the AASM-endorsed consensus for ages 13 to 17. Most teens get far less on school nights, which is why the weekend catch-up never quite works.
Why do teenagers stay up late?
Teen biology shifts the body clock later, so the sleepiness signal arrives later in the evening. It is developmental, not laziness. Fixed wake times still help more than anything else.
What time should a teen go to bed for a 7am school start?
For 8 to 10 hours before a 7:00 wake-up, bedtime should be between about 21:00 and 23:00, minus the time it takes to fall asleep. Use the calculator above with your exact wake time.
Do teens need naps?
A short early-afternoon nap is fine when tired, but long or late naps push bedtime later and make the cycle worse. Keep naps under 30 minutes and before mid-afternoon.
Is this medical advice?
No. These are population guidelines, not a diagnosis. Persistent insomnia, loud snoring, or daytime sleepiness that affects school deserves a clinician's attention.