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Quick answer: IQ scores follow a bell curve with average 100 and standard deviation 15: about 68% score 85-115, only 2% score above 130 (gifted), and only 0.1% score above 145 (near-genius). IQ measures reasoning, not creativity or emotional intelligence.
Looking for solid IQ facts and figures in one place? This is a plain-English reference to the most important IQ statistics — how scores are distributed, how they have changed over time, what they predict, and the myths worth ignoring.
The IQ bell curve
IQ scores follow a normal distribution (a bell curve) with an average of 100 and a standard deviation of 15. That means:
- About 68% of people score between 85 and 115
- About 95% score between 70 and 130
- Roughly 2% score above 130 (the gifted range)
- Only about 0.1% score above 145
The Flynn effect
Across the 20th century, average raw IQ scores rose by roughly 3 points per decade — a trend named the Flynn effect. Because of this, IQ tests are periodically re-standardised to keep the average at 100. In several developed countries the rise has recently slowed or slightly reversed.
Is IQ inherited?
Both nature and nurture matter. Research consistently finds a substantial genetic component to IQ that tends to grow stronger with age — but environment (nutrition, education, health and early stimulation) also has a major influence. Neither genes nor environment alone tells the whole story.
What IQ predicts — and what it doesn’t
IQ is one of the better single predictors of academic and job performance. But it does not measure creativity, emotional intelligence, motivation, character or wisdom — and a high score is no guarantee of success. It captures one slice of human ability, not the whole person.
Does IQ change over your life?
An adult’s IQ is relatively stable, while a young child’s can shift more from year to year. Education, health and environment can nudge scores over time, but dramatic changes are uncommon.
Common IQ myths
- “Your IQ never changes.” Mostly stable in adulthood, but not fixed — especially in childhood.
- “High IQ guarantees success.” It helps, but drive, EQ and opportunity matter just as much.
- “An online test gives your official IQ.” Online tests are useful estimates, not clinical assessments.
- “We only use 10% of our brain.” A popular myth with no basis in neuroscience.
Want to see where you land on the curve? Try a free IQ test for adults, or read our guide to what a good IQ score is by age.
Frequently asked questions
What is the average IQ?
100, by design — about two-thirds of people score between 85 and 115.
What percentage of people are geniuses?
There is no official cut-off, but only about 2% score above 130 and around 0.1% above 145.
Has average intelligence really increased?
Measured IQ scores rose through the 20th century (the Flynn effect), though the trend has recently stalled in some countries.
This article is for general information and summarises widely reported findings; it is not a clinical assessment.
Related free tests
- Free IQ Test for Adults
- Mensa IQ Test
- Classic IQ Test
- IQ Percentile Calculator
- Free IQ Test hub — compare all tests