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When do children become right or left handed?

Hand preference usually starts to show around 6 months of age, becomes more consistent through the toddler years, and is generally well established by age 4 to 6, though it can keep strengthening until about age 9. A clear hand preference showing up before 12 to 18 months is unusual and should be checked by a doctor, since it can (though doesn't always) signal a neurological issue like hemiplegia.

Most children swap hands often between ages 2 and 4 before settling on one, and true 'handedness' in the adult sense isn't reliably measurable until around age 4.

Strength of evidence

Good

Based mainly on observational and cohort studies tracking infants and children over time, plus consistent statements from paediatric guidelines (Canadian Paediatric Society, AAP) on when early hand preference is abnormal. No randomized trials apply here since handedness isn't something to treat, but findings are consistent across many studies.

What the evidence says

Babies often show a slight, inconsistent hand preference for reaching as early as 6 months, and some researchers have even seen lateralized behaviours like thumb-sucking before birth. But this early preference is variable and can shift around quite a bit through infancy and the toddler years. A more settled hand preference for everyday tasks like drawing, throwing, or using a spoon usually develops between ages 2 and 4, and most children have a clearly established dominant hand by age 4 to 6.

The strength of that preference (how consistently they use it) can keep increasing gradually until around age 9. There's one important exception parents should know: pediatric guidelines flag a clear, consistent hand preference appearing before 12 to 18 months of age as unusual. This is because it can be an early sign that the other hand or arm isn't working normally, sometimes due to conditions like cerebral palsy or a perinatal stroke.

It doesn't mean something is wrong, but it's worth mentioning to your doctor so they can check your child's overall movement and tone. There's nothing you need to do to encourage right- or left-handedness. Handedness has strong genetic and neurological roots, and trying to switch a child's preferred hand isn't recommended by any of the guidance reviewed here.

Sources

✓Reviewed by CH, MD, FRCPC

Reviewed by a specialist physician certified by the Royal College of Physicians and Surgeons of Canada, who has read this answer against the sources listed above and confirmed it reflects them. That is not medical advice about your child. How we review

Answer checked August 1, 2026

Educational information only. Not medical advice, not a diagnosis, and no doctor-patient relationship is created by using this. Founded Parent has not examined your child and does not know their history, so this may not apply to you. In an emergency, call your local emergency number. What Founded Parent cannot do

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