Screens before bed: how they affect your sleep, and what to do
Screens before bed can make it harder to fall asleep and shorten your night, but mostly through what you do on them and when you stop, not only through their light. The clearest harm in the research is from using a phone or tablet once you're in bed: it pushes sleep later and is linked to more insomnia. Light from a screen at normal brightness has a smaller effect than many headlines suggest.
So the useful question isn't "are screens bad?" but "which screen habits are costing me sleep?" Below: what the studies actually found, the four ways screens get in the way, a step-by-step plan for the last hour of the evening, what to do instead in the night, and what night mode and blue-light glasses can and can't do.
What the research found
| Study | Who | What it found |
|---|---|---|
| Hjetland et al., Frontiers in Psychiatry, 2025 | About 45,000 students in Norway, aged 18 to 28 | Each extra hour of screen use after going to bed was linked to 59% higher odds of insomnia symptoms and about 24 minutes less sleep. Social media wasn't worse than other screen activities. A survey, so it can't prove cause. |
| University of Otago study, JAMA Pediatrics, 2024 | 85 young teens, filmed with cameras over 4 nights | Screen use in the 2 hours before bed had little effect on that night's sleep. Screen use once in bed made it harder to fall asleep, and interactive use (games, several apps at once) cut sleep the most. |
| Chang et al., PNAS, 2015 | 12 adults in a lab, 4 hours of reading a light-emitting e-reader vs a printed book over several evenings | The e-reader group took about 10 minutes longer to fall asleep, had lower evening melatonin, later body-clock timing and felt less alert the next morning. |
| Studies of phone-free time before bed | Adults and teens asked to stop phone use 30 to 60 minutes before bed for a few weeks | Reported falling asleep faster and sleeping longer than those who kept their habits. |
Two things stand out. First, being in bed with a screen matters more than a screen in the living room an hour earlier. Second, the light effect is real in the lab but was found with long, bright, close-up exposure; with a dimmed phone for 20 minutes it's smaller. Most of the research is in young people, and much of it is surveys, so it shows links rather than proof. Still, the pattern lines up with what is known about how insomnia keeps itself going.
The four ways screens get in the way of sleep
1. They push bedtime later
One more episode, one more video, one more check of the news. Feeds and autoplay have no natural end, so the time you meant to stop slides. Researchers call it bedtime procrastination. If your wake-up time is fixed, every 20 minutes of drift is 20 minutes less sleep.
2. They keep your brain switched on
Email, work chats, arguments in comments, the news and fast games all raise alertness. That's the content, not the light. For someone who already lies awake with a busy head, a stressful message at 10:45 p.m. can cost an hour.
3. They teach your brain that bed is for being awake
This is the part that matters most for people with insomnia. Every night you scroll in bed, the bed becomes a little more linked to being alert. That's why stimulus control, a core part of CBT for insomnia, asks for the bed to be for sleep and sex only. More on that in our guide to stimulus control therapy.
4. Their light nudges your body clock later
Bright light in the evening, especially blue-rich light, tells the brain's clock it's still daytime and holds back melatonin. Phones at full brightness close to the face, laptops, and bright overhead lights all add up. The effect is bigger if you've spent the day indoors in dim light, and smaller if you got plenty of daylight.
Is it the screen or the content?
Mostly the content and the timing. A dim e-reader with a dull novel is a very different thing from a bright phone with work email. A rough ranking, from least to most likely to keep you up:
- Lower risk: a familiar audiobook or calm music with the screen off, a dimmed e-reader with a book you've read, a gentle show you've seen before, on a TV across the room, ending before bed.
- Medium: scrolling photos, light social media, a new episode of a series (the cliffhanger is the problem).
- Higher risk: email and work apps, news, arguments online, shopping, competitive or fast games, anything with notifications, and anything you do while already lying in bed.
How long before bed should you stop using screens?
A common rule from sleep clinicians is to put screens away about an hour before bed, and 30 minutes as a minimum. Use the hour as a buffer zone: the time between "done for the day" and "into bed". If an hour is unrealistic, start with 30 minutes and move it earlier by 10 minutes each week. The bigger win, though, is the rule with no exceptions: no screens in bed at all.
A screen plan for the last hour of your evening
| When | What to do | Why |
|---|---|---|
| 2 hours before bed | Last look at work email and messages. Reply to anything that would worry you overnight, or write it on tomorrow's list. | Stops a late message from switching your brain back on. |
| 90 minutes before | Dim the house lights and turn your phone brightness down. Turn on night mode if you like. | Less light lets melatonin rise on time. |
| 60 minutes before | Screens off, or down to one calm thing on a TV across the room. Phone on silent with notifications off. | The buffer zone begins. |
| 45 minutes before | Plug the phone in to charge outside the bedroom, or across the room. Use a cheap alarm clock if you need one. | Takes away the reach-for-it reflex in bed. |
| 30 minutes before | Wind-down: wash, stretch, read paper pages, slow breathing. | A routine your brain learns as the run-up to sleep. |
| In bed | No screens. If you're awake and alert for what feels like 20 minutes, get up and go to another room. | Keeps the bed linked to sleep. |
Our guide to a bedtime routine for adults fills that last hour minute by minute, with versions for anxiety, parents and late finishers. For caffeine, alcohol and the bedroom, see our sleep hygiene tips.
What to do instead of your phone
- A paper book, ideally one you've read before or one that's a bit dull.
- An audiobook or podcast you know well, with a sleep timer, phone face down across the room.
- A puzzle book, knitting, sketching, a jigsaw.
- A warm shower or bath 1 to 2 hours before bed.
- Writing tomorrow's to-do list and any worries on paper, then closing the notebook.
- Gentle stretching or slow breathing (in for 4 counts, out for 6).
Waking at 2 a.m. and reaching for the phone
Checking the time or scrolling in the night is one of the most common habits in people who wake and can't get back to sleep. Seeing "3:12" sets off a sum ("only 3 hours until the alarm") and the worry wakes you further. The screen's light and content add to it.
- Turn clocks away and keep the phone out of reach.
- If you're awake and calm, stay lying down and let your mind drift.
- If you're awake and alert or frustrated, get up and go to a dim room with a book, and come back when sleepy.
- If you need something to listen to, use a device set up before bed so you don't have to look at a screen.
More on night wakings in our guide to how to stop waking up at night.
Night mode, blue-light filters and glasses: do they help?
Night mode shifts the screen to warmer colours. It lowers blue light but not total brightness, and research on whether it improves sleep is mixed; a 2021 Brigham Young University study of phone users found no clear sleep difference with Night Shift on. Blue-light-blocking glasses have small trials with mixed results, some showing better sleep and others none. Neither touches the bigger problems: the content, the later bedtime, and the phone in bed.
Use them if you like, as a small extra. Turning brightness down and stopping earlier both do more.
What about watching TV to fall asleep?
Many adults fall asleep to the TV and feel it helps. If you fall asleep within minutes and sleep through, it may be harmless. If you have insomnia, it often isn't: you stay up later "for one more", the sound and light can wake you in the night, and you learn that you can only sleep with it on. If you want to wean off it, move the TV time to the sofa before bed, set a sleep timer for 30 minutes, then 20, then switch to audio only with the screen off.
Common mistakes
- Swapping the phone for a tablet in bed. Same habit, bigger screen.
- Banning screens but going to bed too early. If you aren't sleepy, lying in the dark trying to sleep can be worse than the screen was. Go to bed when sleepy.
- Using "do not disturb" but keeping the phone on the pillow. The reach still happens.
- Changing everything at once. Start with one rule (phone charges outside the bedroom) and keep it for two weeks.
- Blaming screens for everything. If you still can't sleep after dropping them, the cause is elsewhere. See below.
When screens aren't the real problem
If you lie awake most nights, three nights a week or more, for three months, even after cutting screens, that's chronic insomnia, and the habits that keep it going are usually time in bed, worry and an irregular schedule. Our guide to CBT for insomnia techniques covers the methods that target those. See a doctor if you snore loudly or stop breathing in sleep, have restless legs, feel very low, or your sleep changed with a new medicine. The free 2-minute sleep quiz works out how much time you spend awake in bed, which tells you if more than habits are in play.
Frequently asked questions
Is it bad to use your phone before bed?
An hour of calm use on the sofa matters less than use in bed. Stop 30 to 60 minutes before bed, keep it dim, avoid work and news, and keep it out of the bed.
Does blue light really keep you awake?
Bright, blue-rich light in the evening can hold back melatonin and shift your body clock later, as lab studies show. A dimmed phone for a short time has a smaller effect. Content and timing matter more for most people.
Is reading on a Kindle before bed OK?
A dim e-ink reader without a backlit glare is closer to a paper book than a phone. A bright backlit tablet is closer to a phone. Read in a chair, not in bed, if you have insomnia.
How much sleep do screens cost?
It varies. In the 2025 Norwegian study, each extra hour of screen use in bed was linked to about 24 minutes less sleep. In a lab, reading a light-emitting e-reader before bed added about 10 minutes to the time it took to fall asleep.
Can I listen to podcasts in bed?
If the screen stays off and the podcast is calm and familiar, many people find it fine. Use a sleep timer. If it keeps you listening instead of sleeping, move it to before bed.
Start tonight
Pick one change: tonight, charge your phone outside the bedroom and set a cheap alarm clock instead. Next week, add a 30-minute screen-free buffer before bed. To see how much time you spend awake in bed, take the free sleep quiz. For more on winding down, schedules and night waking, see all our sleep guides.
Sources: Hjetland GJ et al., Screen use in bed and sleep: a large-scale survey of Norwegian students, Frontiers in Psychiatry, 2025 (doi 10.3389/fpsyt.2025.1548273). Taylor RW et al. (University of Otago), objective screen use before and in bed and adolescent sleep, JAMA Pediatrics, 2024, as reported by Sleep Review, September 2024. Chang AM et al., Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness, PNAS, 2015. Duraccio KM et al., Does iPhone Night Shift mitigate negative effects of smartphone use on sleep outcomes in emerging adults?, Sleep Health, 2021. Edinger JD et al., American Academy of Sleep Medicine clinical practice guideline on behavioural treatments for chronic insomnia, 2021. This guide is education, not medical advice.