There is no official daily limit for a 12-year-old: the UK Chief Medical Officers said the evidence was not strong enough to set one. What the guidance does stress is habits, especially keeping phones out of the bedroom at bedtime, so the useful question is what your child is doing on the screen and when.
Homework, revision and study apps all live on screens now, which makes the old "two hours a day" rule hard to apply. Here is a practical way to think about it, and a routine you can adapt.
What UK guidance actually says
In 2019 the UK Chief Medical Officers published a commentary on screen-based activities. It said scientific research was insufficiently conclusive to support evidence-based guidelines on optimal amounts of screen use, and that screen time can displace health-promoting activities such as sleep, so families should try to find a healthy balance. It gave advice for parents and carers, which includes:
- leave phones outside the bedroom at bedtime
- have screen-free meal times
- take a break after a couple of hours sitting or lying down using a screen
- put screens away during activities that need full attention, such as crossing the road
On sleep, the NHS says most teenagers need 8 to 10 hours a night. The sleep medicine team at Evelina London Children's Hospital (an NHS hospital) advises teenagers to stop using a phone or tablet at least an hour before bed and to charge the phone anywhere but the bedroom.
Notice what is missing: no magic number. That frees you to judge by quality and by what gets crowded out.
Productive or passive? Four quick questions
Instead of timing it, ask:
- Is my child producing something? Answering questions, writing, making cards, solving problems is active. Watching, scrolling or re-reading is passive.
- Could they tell me what they learned? If not, it was probably passive.
- Is it one task or many tabs? Notifications and switching cost attention.
- What did it replace? Sleep, exercise, friends and real breaks are what to protect.
Study apps can land on either side. A quiz app that makes your child recall facts is active. A video playlist left running is usually not.
A simple routine that works
Phone-free study block. Agree 25 to 40 minutes of work, phone in another room rather than face-down on the desk, then a proper break. Short and finished beats long and leaky.
One device, one job. If the laptop is for homework, the phone is not on the desk. If an app is needed on the phone, turn off other notifications for the block.
Anchor it to the day. Same time most days, after a snack and a break, not at 9.30pm.
Protect the end of the day. Set a rough "screens off" time at least an hour before bed (in line with the Evelina London advice), and charge phones outside the bedroom. Sleep matters for memory and mood, so a late revision session can cost more than it gains.
A script for the agreement: "Let's try this for two weeks. Phone in the hall during homework, and I'll put mine away at the same time. Then we look at how it went."
Doing it together matters. A rule your child experiences as a punishment will be hidden from you; a plan they helped shape is more likely to stick.
- After school1Snack and break
- 25 to 40 min2Phone-free blockPhone in another room
- 3Proper break
- 60 min before bed4Screens offPhones charge outside the bedroom
Choosing study apps with screen time in mind
Good study tools are built so that a session ends. Look for:
- a clear task and a clear finish, not an endless feed
- no pressure tactics, such as "you will lose your streak" warnings
- a prompt to do something with what was learned
Heddy, for instance, is designed so that a session has a shape: a problem with a tutor, then flashcards from that session, reviewed on a schedule with a fixed twenty cards a day. It also avoids loss-framing in its streak language, described in what Heddy deliberately will not do. It is for students aged 13 and over, so check age ranges for any tool you choose.
If the apps are AI-based, read AI and homework: what parents should know.
Signs to step back
Screens are not the cause of every problem, but watch for:
- sleep getting later or shorter
- schoolwork being done in the dark, in bed
- irritability when the device is removed, beyond the usual
- avoiding friends or activities they used to like
If worries build, the NHS suggests a GP as a good starting point for persistent low mood or anxiety, and Childline (0800 1111) is free and confidential for young people. There is more in exam stress in KS3. And if homework volume is what drives late-night screen use, read how much homework is normal in KS3.
Updated 30 Sep 2026. Written by Duke Harewood, who builds the tutors at aitutors.me.
Questions people ask
How much screen time is OK for a 12-year-old?
The UK Chief Medical Officers did not set a daily time limit, because they judged the evidence insufficient. Their advice focuses on habits: phones outside the bedroom at bedtime, breaks, and screen-free mealtimes.
Does studying on a screen count as screen time?
It is still screen use, but it is not all the same. Active use (answering questions, making something) is different from passive scrolling. Ask what your child is doing rather than only how long.
When should screens stop before bed?
An NHS children's hospital sleep team advises teenagers to stop using phones and tablets at least an hour before bed and to charge the phone outside the bedroom; the UK Chief Medical Officers likewise advise leaving phones outside the bedroom at bedtime.
How can I stop my child getting distracted by their phone while studying?
Agree a phone-free study block, keep the phone in another room, and use one device for one job. Short, defined sessions work better than open-ended ones.