Average IQ: what is normal
On professional tests the average is set to 100, and about two thirds of people score between 85 and 115.
Why the average is 100
Test publishers give a test to a large group that represents the population and then set the scores so that the middle of that group is 100. With 15 points per step, the usual ranges follow from the shape of the bell curve.
What counts as a normal IQ
There is no single line, but the range from 85 to 115 holds about 68% of people, and from 70 to 130 about 95%. Scores in these ranges are common.
Average IQ by age
Each age group is compared only with people of the same age, so the average is 100 for children, adults and older people alike. A ten-year-old with 100 and a sixty-year-old with 100 are both in the middle of their own age group.
| Range | Share of people |
|---|---|
| 85 to 115 | about 68% |
| 70 to 130 | about 95% |
| 55 to 145 | about 99.7% |
Has the average changed over time?
Yes. Raw test performance rose in many countries during the 20th century, which is called the Flynn effect. A 2015 meta-analysis of studies from 1909 to 2013 found gains of about 2.8 points per decade for full-scale IQ, with smaller gains in recent decades. Publishers re-norm their tests, so the average is moved back to 100.
Why we do not list average IQ by country
Country comparisons mix different tests, samples and years, and the data behind popular lists is disputed. We do not publish such numbers.
Where our test fits
Our free test gives an estimate on a provisional scale, not a normed IQ score, so it cannot place you against this average.
Sources
Last checked: 2026-11-03
A summary of published research, not medical, career or psychological advice. A correlation describes groups, not any one person. This text has not yet been reviewed by a psychologist.