At What Age Can a Child Take an IQ Test?

Which Test at Which Age

For toddlers (roughly 1–3), the Bayley Scales assess developmental milestones rather than IQ proper. The WPPSI-IV covers ages 2.5 to 7.5, the WISC-V spans 6 to 16, and from 16 up examinees take the adult WAIS-IV. The Stanford-Binet 5 covers ages 2 through 85 with age-adjusted item sets.

Because every score is normed against same-age peers, a 6-year-old and a 40-year-old scoring 115 both sit at the same percentile within their own age group.

When Testing a Child Makes Sense

Schools typically test between ages 5 and 8 for gifted-program placement, and at any age when learning difficulties, developmental delays, or large gaps between ability and performance need investigation. Early scores should be treated as provisional: childhood IQ can shift 10–20 points into adolescence as the brain develops.

For parents, the practical guidance is to test when there's a decision the result would inform — program eligibility, support services, or diagnostic clarity — rather than out of curiosity. A professional evaluation also yields subtest profiles far more useful than the single number.

How stable is a child's IQ score?

Scores measured before age 5 correlate weakly with adult IQ. From ages 6–8 the correlation strengthens considerably, and by adolescence scores are quite stable — though individual shifts of 10+ points still occur.

What IQ qualifies a child as gifted?

Most US gifted programs use a cutoff around 130 (98th percentile) on a professionally administered test like the WISC-V, though some districts use lower thresholds or broader multi-criteria assessments.

Can toddlers take IQ tests?

Instruments exist from age 2 (WPPSI, Stanford-Binet Early SB5), and developmental scales from infancy. But early results mainly screen for developmental concerns — they're poor predictors of later intelligence.