The average IQ score by definition is exactly 100, with a standard deviation of 15. In modern psychometric testing, the average range is defined as scores between 90 and 109, which encompasses approximately 50% of the entire human population under the standard normal distribution curve.
📌 Population Intelligence Baselines
Exact Mean / Median
IQ 100.0
Normal Range (50% of people)
IQ 90 to 109
Broad Average (68% of people)
IQ 85 to 115 (±1 SD)
Flynn Effect Rate
~3 Raw Points per Decade
Why 100 is always the average IQ
A frequent point of confusion is whether the population's average IQ can rise to 105 or fall to 95. In psychometrics, the answer is no: 100 is not a raw score, but a calibrated benchmark. When test publishers like Pearson standardise a new edition of the WAIS, they administer the test to thousands of individuals representing census demographics, and adjust the scoring tables so that the sample average is anchored at 100.
The Flynn effect: why tests must be renormed
In 1984, political scientist James Flynn documented that raw performance on cognitive tests had been rising steadily by approximately 3 IQ points per decade throughout the 20th century across industrialised nations. This phenomenon, known as the Flynn effect, means that if an average person from 2026 took an IQ test standardized in 1950, they would score significantly higher than 100.
What drives changes in raw cognitive performance?
Improved Nutrition and Health: Eradication of childhood infectious diseases and better prenatal care.
Cognitive Complexity in Work: Modern careers require abstract problem solving, software interaction, and symbolic logic.
Visual-Spatial Media Exposure: Proliferation of digital interfaces and visual media training nonverbal reasoning.
While raw cognitive test familiarity and education improve performance, your relative deviation score among peers of the same age remains relatively stable in adulthood.
What percentage of the population has an average IQ?
Approximately 50% score in the average range (90–109), and 68.2% score within the broad average range of 85–115.
Researchers, educators, and content publishers may reference this analysis using the citation hyperlink below:
<a href="https://iq-test.icu/iq-scores/average-iq" title="https://iq-test.icu/iq-scores/average-iq">APEX IQ Test — IQ SCORES AVERAGE IQ</a>
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