How much screen time is OK for under-fives? What the WHO limits actually say

The honest short answer is that the major guidelines set firm age-based limits — no sedentary screen time at all for children under two, and no more than one hour a day, less being better, from two to four years — but the research those limits rest on shows a modest association, not proof that screens directly damage development [s1][s3][s2]. The numbers are worth knowing precisely, and so is the uncertainty behind them.

What the limits actually are

The World Health Organization's guidelines on physical activity, sedentary behaviour and sleep for children under five are specific by age [s1]. For infants under one year, "screen time is not recommended," and when sedentary they should instead be read to or told stories by a caregiver [s1]. For one-year-olds, "sedentary screen time (such as watching TV or videos, playing computer games) is not recommended" [s1]. For those aged two, "sedentary screen time should be no more than 1 hour; less is better" [s1]. And for children aged three to four, sedentary screen time should again be "no more than 1 hour; less is better" [s1].

The American Academy of Pediatrics reaches similar conclusions in its policy on media and young children: it advises avoiding use of screen media other than video-chatting for children younger than 18 months, and limiting screen use to one hour a day of high-quality programming for children aged two to five, watched together with a parent where possible [s3]. Both bodies frame the limits less as a hard toxicity threshold and more as protecting time for the sleep, play and interaction that young children need [s1][s3].

What the evidence underneath shows

The developmental evidence is real but should not be overstated. A widely cited longitudinal study of 2441 mothers and children in Calgary, Canada, tracked screen time and development at ages 24, 36 and 60 months using the Ages and Stages Questionnaire, a standard developmental screening tool [s2]. Using a statistical model that separates change within a child from stable differences between children, the researchers found that higher screen time at 24 and 36 months was significantly associated with poorer developmental screening scores at 36 months (β −0.06, 95% confidence interval −0.10 to −0.01) and at 60 months (β −0.08, 95% CI −0.13 to −0.02) [s2].

Those are small effect sizes, and the study's own framing is important: it set out to test the direction of the relationship, because it was "unclear if greater screen time predicts lower performance" or whether children with poorer development are simply given more screen time to manage difficult behaviour [s2]. The analysis supported screens preceding the lower scores rather than the reverse, but this is a single observational cohort — it cannot prove cause and effect, and the size of the association is modest [s2]. That is the responsible way to read it: a reason to favour the guideline limits, not evidence that an hour of television will hold a child back.

How to use this

The practical takeaway is that the guidance is clear and easy to apply even if the underlying science is nuanced: keep screens away from babies and one-year-olds, cap screen time at around an hour from age two, choose good-quality content, watch it with your child where you can, and protect sleep and active, interactive play [s1][s3]. The AAP's emphasis on co-viewing and on avoiding screens around bedtime reflects that what a child is doing instead of the screen — and whether an adult is engaged with them — matters as much as the raw minutes [s3].

Related questions sit alongside this: how much sleep young children actually need is covered in how much sleep children need by age. This article is informational and not medical advice; a health visitor or GP can advise on an individual child's development if you have concerns [s2].