Parents should worry less about how much time their children spend using screens, paediatricians have said.
The first UK guidance on screen use for children says there is little evidence that it is harmful in itself.
But experts say it is important that the use of devices does not replace healthy activities, such as sleep, exercising and time with family.
The guidance avoids setting screen time limits, but does recommend not using them in the hour before bedtime.
It was informed by a review of evidence published at the same time, and follows a debate around whether youngsters should have time on devices restricted.
'Great way to explore'
The Royal College of Paediatrics and Child Health (RCPCH), which has produced the guidance for under-18s, said there was no good evidence that time in front of a screen is "toxic" to health, as is sometimes claimed.
While there are associations between higher screen use and obesity and depression, the college said it was not clear if this link was causal.
The college said it was not setting time limits for children because there was not enough evidence that screen time was harmful to child health at any age.
Instead, it has published a series of questions to help families make decisions about their screen time use:
- Is your family's screen time under control?
- Does screen use interfere with what your family want to do?
- Does screen use interfere with sleep?
- Are you able to control snacking during screen time?
Dr Max Davie, officer for health promotion for the RCPCH, said phones, computers and tablets were a "great way to explore the world", but parents were often made to feel that there was something "indefinably wrong" about them.
He said: "We want to cut through that and say 'actually if you're doing OK and you've answered these questions of yourselves and you're happy, get on and live your life and stop worrying'.
"But if there are problems and you're having difficulties, screen time can be a contributing factor."
The recommendation that children should not use the devices in the hour before bedtime comes because of evidence that they can harm sleep.
The devices stimulate the brain, and the blue light produced by them can disrupt the body's secretion of the sleep hormone melatonin.
While there are night modes on many phones, computers and tablets, there is no evidence these are effective, the college said.
Overall, it found the effect of screen time on children's health was small when considered next to other factors like sleep, physical activity, eating, bullying and poverty.
It said there was a lack of evidence that screen time is beneficial for health or wellbeing.
Its guidance recommends that families negotiate screen time limits with their children based on individual needs and how much it impacts on sleep, as well as physical and social activities.
For infants and younger children, this will involve parents deciding what content they watch and for how long they use the devices.
As children get older, there should be a move towards them having autonomy over screen use, but this should be gradual and under the guidance of an adult, the college said.
Dr Davie added: "When it comes to screen time I think it is important to encourage parents to do what is right by their family.
"However, we know this is a grey area and parents want support, and that's why we have produced this guide.
"We suggest that age-appropriate boundaries are established, negotiated by parent and child, that everyone in the family understands."
Tips for parents:
- Mealtimes can be good opportunities for screen-free zones
- If children's screen time use seems out of control, parents should consider intervening
- Parents should think about their own screen use, including whether they use devices unconsciously too often
- Younger children need face to face social interaction and screens are no substitute for this
Meanwhile, a separate study has found that girls are twice as likely to show signs of depressive symptoms linked to social media use at age 14 compared with boys.
The research, by experts at University College London and published in EClinicalMedicine, involved nearly 11,000 young people answering questionnaires on their social media use, online harassment, sleep patterns, self-esteem and body image.
Experts not involved in the study said it added to existing evidence that heavy social media use may be harmful for mental health.
But they called for more research to better understand if it causes depression, or if depressive people are more likely to use social media excessively.
The review of evidence on screen time is published in the BMJ Open journal.