Phones in the evening & at night: how screen time affects your teen's sleep

What this is really about

We mean the ordinary evening: quickly reading the last messages, one video, a few rounds of a game — and when a notification lights up at night, a quick look. For many teenagers the phone is part of falling asleep, the way a bedtime book used to be.

How common is this?

Around 95% of 12- to 19-year-olds own their own smartphone (JIM Study 2025). For most, it's within reach at night — in or right next to the bed. The last glance at the screen before sleep and the first one after are everyday life in many families. So your child isn't the exception, but the rule.

What it does to sleep

A recent study, contextualised by the German Brain Foundation, shows that teenagers who reach for their phone more often and for longer at night fall asleep later and sleep worse. And sleep at this age isn't a luxury — it's the time when the brain, focus and mood recover.

Worth noting: the much-cited "blue light effect" is scientifically contested and probably smaller than assumed. The three bigger sleep thieves are more mundane — and precisely for that reason changeable:

• The phone simply displaces sleep time — "just one more video" quickly becomes an hour.
• Exciting content and chats wake you up rather than wind you down — the mind can't settle.
• Notifications arriving at night pull you out of deep sleep, often without you knowing in the morning.

Why it's so hard to put the phone down

The evening phone meets real needs: staying in touch, winding down from the day, not missing out. Ignoring that and just confiscating the device takes something away without offering a replacement — and earns resistance instead of insight. It works better to take the need seriously and find better ways together.

How teenagers experience it themselves

The surprising part: most teenagers already know they're not getting enough sleep. They feel the tiredness in class. The problem isn't a lack of insight, but that putting the phone down is harder than it sounds:

• In bed it's quiet and boring — the phone fills that emptiness instantly.
• When the group chat is still going, going offline feels like walking out mid-conversation (FOMO).
• Reaching for the phone has become a habit — the hand almost does it on its own.

When you acknowledge this instead of dismissing it as laziness, your child feels understood — the basis for them wanting to change anything at all.

What actually helps

Not the big ban, but small steps agreed on together. What works in many families:

• A charging spot outside the bedroom: the phone charges overnight in the kitchen or hallway — the simplest and most effective lever.
• A real alarm clock: if you don't need the phone as an alarm, there's no reason to keep it by the bed.
• A phone-free hour before sleep — for the whole family, not just the kids.
• Silence notifications at night (focus or sleep mode) so nothing pulls you out of sleep.
• Step by step rather than radical: first put it away half an hour earlier, then more.

Why this works

Once the stimuli are gone, falling asleep gets easier — the bed becomes a place of rest again, not entertainment. What's decisive is the how: rules your teen helps set are carried along; top-down bans get bypassed. And when parents put their own phone away in the evening, that says more than any lecture.

What's worth talking about

Don't start with a rule, but with an honest question — in a calm moment, not at 11 p.m. by the bedroom door:

• "How well are you actually sleeping right now — honestly?"
• "What would make putting it away in the evening easier for you?"
• "Shall we try the phone-free hour together — I'll join in?"

This is exactly where Digital Mastery comes in: both sides rate the same everyday life and see where the evening phone really becomes an issue — a fair basis for a conversation as equals instead of the next argument.