What time should teens stop using their phone? Try 10 p.m.

The question parents keep typing into search bars, what time should teens stop using their phone, now has a reasonable answer: 10 p.m. on school nights, or an hour before lights-out if bedtime comes earlier. That rule comes from a study published on 19 October 2026 in JAMA Pediatrics, one of the first to point at a specific cutoff time instead of a vague call for less screen time.

According to HealthDay, on nights when teens used their phone after 10 p.m. more than they usually did, they fell asleep about 64 minutes later and slept about 20 minutes less. Phone use in the 5 to 15 minutes right before falling asleep was linked to more waking during the night. The study can't prove the phone caused any of this, though its design makes it harder to wave away than most screen-time research.

What the JAMA Pediatrics study found in 425 teens

The paper, "Evening Phone Use and Sleep Outcomes Among Youth" by Yihong Zhao and colleagues, comes from a team led by Dr. Dimitri Christakis at Seattle Children's Research Institute. They looked at 425 kids with an average age of nearly 15, drawn from an ongoing study of adolescent brain development, covering nearly 7,600 nights of data (Medical Xpress).

The useful part is how they compared. Each teen was measured against their own typical night, rather than against other teens. A teen with strict parents, an early school bus or a naturally late body clock is still only compared with themselves, so those differences can't explain the result.

The 64-minute figure needs a little care. The coverage describes it as the delay on nights of above-usual use after 10 p.m., while one HealthDay takeaway says every extra minute past 10 added to the delay. We're working from news reports of the paper, so treat 64 minutes as a sign of a sizable effect. It doesn't mean a single late video costs your teen a full hour.

The authors' own conclusion is modest: cutting evening phone use, especially after 10 p.m. and right before bed, may help teens sleep.

The evidence is observational, and one small study points the other way

Medical Xpress states plainly that the associations "do not establish causation." The obvious alternative is reverse causation. A teen who is lying awake anyway might reach for the phone, which would make late use a symptom of bad nights as much as a cause.

Comparing teens with themselves helps, because it rules out stable traits like personality or family rules. It can't rule out a stressful week in which a teen both sleeps badly and scrolls more. The honest reading is a consistent link that fits the idea of late phone use pushing sleep back, with the cause still unproven.

An adult study found slightly more sleep with in-bed phone use

In February 2026, a study in PLOS Digital Health tracked 68 people for 14 days using iPhone and Apple Watch data. In-bed phone use was linked to slightly more sleep that day. The authors said this cuts against the idea of phones as sleep disruptors, though they couldn't tell whether the extra time asleep meant poorer rest.

It's worth knowing about, and it doesn't overturn the teen findings. The sample was small, the participants weren't described as teenagers, and two weeks is a short window. A teen study with 7,600 nights and a general study with 68 people are answering different questions.

Two other 2026 studies show late use feeding on itself

Scrolling before bed predicted scrolling after midnight

Researchers at Stony Brook presented an abstract at the SLEEP 2026 meeting on 230 US teens whose phone use was measured by an app called RealityMeter for about 17 days (AASM via EurekAlert). On nights with an extra 20 minutes of use in the hour before bed, teens racked up 8 to 9 more minutes of use between midnight and 5 a.m. on school nights. It's a conference abstract, so it hasn't been through full peer review yet.

In a community new to smartphones, users' body clocks ran 34 minutes later

A study in the journal Sleep followed 100 people in Toba/Qom Indigenous communities in northern Argentina, where smartphones arrived only recently. Wrist sensors tracked 8,407 nights. Smartphone users fell asleep 13 minutes later and slept 22 minutes less than non-users, and their melatonin onset (a marker of the body clock) came 34 minutes later.

Put together, these hint at two things going on. The melatonin result suggests the body clock itself gets nudged later. The Stony Brook result suggests the bigger everyday problem may be that a bit of scrolling before bed turns into a lot of scrolling after midnight. Neither shows blue light is the main culprit, so we wouldn't count on a night-mode filter to fix this on its own.

What time should teens stop using their phone? 10 p.m. or an hour before bed

The American Academy of Sleep Medicine recommends 8 to 10 hours of sleep for ages 13 to 18, and devices off 30 to 60 minutes before bed (AASM via EurekAlert). Combine that with the JAMA Pediatrics finding and you get a simple rule: phones go away at 10 p.m. or 60 minutes before lights-out, whichever comes first.

For many teens, the hour-before-bed part will kick in first. If your teen has to be up at 6:30 for school and you're aiming for 9 hours, lights-out is 9:30 and the phone goes away at 8:30. The 10 p.m. line is the backstop for nights when bedtime drifts.

How to make a phone curfew for teens stick

A rule that gets fought every night won't last long. These steps lean on what the studies found, and where something is our own reasoning, we say so.

1. 01
   Protect the last 15 minutes

   Use right before sleep was the part linked to more waking in the night, so guard this window hardest.

2. 02
   Trim the pre-bed hour

   In the Stony Brook data, extra use before bed predicted extra use after midnight, so cutting the earlier session should shrink the later one too.

3. 03
   Charge the phone outside the bedroom

   Neither teen study tested this directly, but it's the most obvious way to remove those 46 minutes of average late-night use.

4. 04
   Go after feeds first

   This one is our own reasoning. Reels, Shorts and TikTok have no natural end while a quick message to a friend does, so blocking feeds after 10 p.m. and leaving messages and alarms on is an easier sell.

5. 05
   Make it a household rule

   Parents keeping the same cutoff makes it feel less like a punishment. That's general parenting sense, and these studies didn't measure it.

6. 06
   Ease off on one-off late nights

   The effects are averages from observational data, so the usual pattern matters far more than the occasional sleepover or exam cram.