What Is the Average IQ? By Age, Range & Global Norms

Most people know that 100 is the average IQ score, but fewer realize that this number is less a fixed measurement and more a statistical anchor—calibrated to make every age group comparable to itself. Age-norming keeps the average at 100 for every age group. That single concept explains most of the confusion around IQ averages by age, country, and even gender. What follows is a breakdown of what the numbers actually mean, where the data comes from, and what remains genuinely unclear.

Global Average IQ: 100 · Normal Range: 85-115 · % in Average Range: 68% · Standard Deviation: 15 · Adult Average: 100

Average IQ score by age

A common misconception is that IQ declines steadily as people age. In raw terms, some cognitive abilities do peak in young adulthood and slow later. But IQ tests are specifically designed to account for this through a process called age-norming, which keeps the average at 100 for every age group.

IQ norms from childhood to adulthood

Age-norming compares each individual only to peers in their same age bracket. A 20-year-old is measured against other 20-year-olds; a 60-year-old is measured against other 60-year-olds. This means the average IQ stays at 100 within every age group—not because cognition is identical across ages, but because the scoring system adjusts for it.

Standardization across ages

• Raw scores on fluid intelligence tasks peak in the mid-20s
• Crystallized intelligence (learned knowledge) often rises through middle age
• Age-norming blends both to produce stable average IQ across the lifespan

Large-sample data from the International IQ Test (2026) shows reported averages for different age brackets: adults aged 30-39 reported averages around 100.4, while those 60-69 showed lower reported averages before norming adjustments.

Test-specific adjustments

Different IQ tests use slightly different norming tables. The WAIS-IV, for example, uses age bands of roughly 10 years, while the WISC (for children) uses narrower bands to account for faster developmental changes in youth.

What is the average IQ of a person in the world?

The worldwide average IQ is set at 100 by design. IQ tests are built so that when a large, representative sample of people takes the test, the average score lands exactly at 100 with a standard deviation of 15. This is not a coincidental finding—it is a standardization convention that makes IQ scores interpretable across populations and time periods.

Global standardization at 100

The Wechsler Adult Intelligence Scale (WAIS-IV), Stanford-Binet, and most other major tests all use this same anchoring method. IQ scores typically range from 70 to 145 or higher, but the distribution follows a bell curve. Roughly 68% of people score between 85 and 115, which represents one standard deviation above and below the mean.

Distribution bell curve

• Below 70: Intellectual disability range
• 70-79: Borderline range
• 80-89: Low average
• 90-109: Average range
• 110-119: High average
• 120-129: Superior
• 130+: Very superior

The WAIS-IV classifications show that the “average” band of 90-109 covers the middle third of the population, while only about 2% of people score above 130—the threshold often associated with giftedness.

Percentiles overview

On a standard IQ distribution, percentile ranks map directly to standard deviations. A score of 115 places a person at the 84th percentile—meaning they scored higher than roughly 84% of test-takers. A score of 130 places someone at approximately the 98th percentile.

What is the average IQ for a 12 year-old?

For children around age 12, the average IQ score on age-normed tests is also 100. This is true by definition—IQ tests for children, such as the WISC (Wechsler Intelligence Scale for Children), are normed so that the average within each age group lands exactly at 100. What varies is the range of individual scores, which tends to be wider in younger children than in adults.

Childhood IQ norms

Children’s cognitive development is uneven. A 12-year-old may excel at verbal reasoning but still be developing spatial skills, or show advanced crystallized knowledge alongside maturing fluid reasoning. IQ tests for children measure multiple domains and combine them into a composite score, which is then compared to a norming sample of same-age children.

Comparison to adult scales

• WISC for children: age-normed to 100 within each age band
• WAIS for adults: same principle, different norming tables
• Standard deviation of 15 applies at all ages

The WAIS-IV classification system applies conceptually to children as well: 90-109 is the average range, 80-89 is low average, and so on. However, clinical interpretation of children’s IQ scores places greater weight on developmental context.

Developmental factors

Factors such as nutrition, early education access, health conditions, and socioeconomic status all influence cognitive development and IQ scores in children. Research consistently shows that these environmental factors contribute significantly to measured IQ differences between groups.

The implication for parents and educators is that a single IQ score for a 12-year-old reflects where they stand relative to peers right now—not a fixed ceiling on their cognitive potential.

What is the average IQ for a teenager?

Teenagers—typically defined as ages 13 to 19—also average 100 on age-normed IQ tests. The adolescent years bring rapid brain development, particularly in the prefrontal cortex, which handles planning, impulse control, and abstract reasoning. These changes are reflected in test performance but are accounted for by norming.

14 year old averages

At age 14, most adolescents are transitioning from concrete operational thinking to more formal operational thinking, according to developmental psychology frameworks. IQ tests capture this shift within their age-norming process, so the average remains 100 regardless of the cognitive changes underway.

16 year old averages

By age 16, many teenagers have reached near-adult levels of fluid reasoning capacity, though crystallized knowledge continues to accumulate. Reported data from large samples shows averages hovering around 100 for this age group, with some non-normed samples reporting slightly higher or lower figures.

Teen variability

• Puberty timing varies by several years between individuals
• Brain development and cognitive performance are loosely correlated during adolescence
• Standard deviation of 15 means most teens fall between 85 and 115

For teenagers, parents and educators should not over-interpret a single IQ score. The developmental window is wide, and test performance can fluctuate based on motivation, sleep, and emotional state.

What this means for families is that adolescent IQ scores capture a snapshot of current cognitive standing relative to peers, not a prediction of adult capability.

What is the average IQ for an adult?

Adults, like all other age groups, average 100 on age-normed IQ tests. The normal adult range is defined as 90-109, which represents the central 50% of the adult population. This range is slightly narrower than the 68% band (85-115) that applies to the general population across all ages.

Age 25 and beyond

After age 25, raw cognitive performance on certain tasks—particularly those involving processing speed and working memory—begins a gradual decline. However, crystallized intelligence, accumulated knowledge, and verbal abilities often remain stable or even improve through middle age. Age-norming blends these factors to keep the average at 100.

Adult range details

• 90-109: Average (covers roughly half of all adults)
• 80-89: Low average
• 110-119: High average
• Above 120: Superior range
• Below 80: May warrant clinical evaluation

Data from NCH Stats shows the US national average IQ is approximately 98, which falls slightly below the theoretical 100. Researchers attribute this to sampling differences, educational attainment variations, and methodological differences between studies rather than actual lower intelligence.

Global adult norms

The 2019 Intelligence of the Nations report by Richard Lynn and Dania Van Gasse (University of Ulster) found that developed nations tend to have higher average IQs, with Japan at 106.48, Taiwan at 106.47, and Singapore at 105.79 leading globally. The US ranked 31st with an average of 97.43.

Within the US, state-level averages show variation: Massachusetts averages around 103-104, while states like Mississippi and New Mexico average closer to 95. These differences correlate strongly with educational investment and socioeconomic factors.

The pattern across nations shows that countries investing heavily in education and health infrastructure tend to produce higher average IQ scores on standardized tests.

Quotes

IQ tests use age-based norming that compares individuals only to others of the same age, and the average is always arbitrarily set to 100.

— Riot IQ (IQ Analysis Resource)

Ages 26-35 show the highest average IQ scores, likely due to educational completion and cognitive maturity.

— IQ Frontal Lobe (Statistics Aggregation)

The average IQ has increased by 3 points per decade since 1900.

— IQ Frontal Lobe (Statistics Aggregation)

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While the average IQ is standardized at 100 across populations, detailed IQ breakdowns by age highlights key variations by age group and region from verified data.

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