— IQ across the lifespan

Average IQ at age 5

Age-normed avg

100

Life stage

Early childhood

Std deviation

±15

Population %ile

50th

The average IQ at age 5 is 100 by definition. IQ tests are age-normed — each person's score is compared against the typical performance of their own age group, not against an absolute scale. This means a "100" at age 5 is calibrated to whatever typical 5-year-olds actually score.

What's actually happening cognitively at 5

Age 5 falls in Early childhood — characterized by rapid working-memory development, fluid intelligence still consolidating, pattern recognition emerging. The age-normed IQ of 100 conceals real developmental shifts: certain cognitive abilities peak at different ages, even though the test's scoring system rescales everyone to a mean of 100.

Fluid vs crystallized intelligence at age 5

IQ has two large components that age differently:

Fluid intelligence (raw reasoning, pattern recognition, novel problem-solving) is still rising at age 5 and will peak between 18 and 22.
Crystallized intelligence (vocabulary, accumulated knowledge, expertise) is still rapidly accumulating at age 5.

What "average" looks like at age 5

An IQ of 100 at age 5 means typical performance for the 5-year-old age cohort on the following tasks:

Vocabulary and verbal comprehension at a developmentally typical level for elementary/middle school
Working memory — typical capacity of holding 5-7 items active at once
Processing speed — near lifetime peak
Abstract pattern recognition — typical for the cohort

What's YOUR IQ at age 5?

Take a 20-minute calibrated test and see your composite IQ plus your six-axis cognitive profile.

Common misconceptions about IQ and age

"My IQ is going down as I age." Your age-normed IQ stays roughly constant — the test rescales for your cohort. What changes is raw fluid performance; crystallized knowledge typically increases.
"Kids who score higher are more intelligent than adults." Age-normed IQ is the only fair comparison. A 12-year-old scoring 130 and a 50-year-old scoring 130 both rank at the 98th percentile within their own age group.
"Peak IQ is at age 25." Different components peak at different ages: working memory and processing speed in the early 20s; verbal/crystallized knowledge in the 50s-60s; composite age-normed IQ is roughly stable from early adulthood through middle age.

Frequently asked

What is the average IQ at age 5?

100 by definition. All standard IQ tests (WAIS, Stanford-Binet, WISC) are age-normed so the mean is always 100 for the specific age cohort being tested.

Does IQ drop with age?

Age-normed IQ stays roughly constant from early adulthood through middle age. Raw fluid intelligence declines after age 25-30; crystallized intelligence grows until 50-65; both are baked into the age-normed score.

Can my child be tested for IQ at age 5?

Reliable IQ testing typically begins around age 6. Before that, infant cognitive assessments use different scales (Bayley, Mullen) that don't predict adult IQ well.