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Quick answer: The IQ scale is built so that 100 is always the average score with a standard deviation of 15, so about 68% of people score between 85 and 115 and only around 2% score above 130 (the gifted range).
An IQ score only makes sense once you know the scale behind it. Here is the IQ scale explained in plain English — what 100 means, the full classification chart, and what actually counts as a “genius” IQ.
How the IQ scale works
Modern IQ tests are built so that 100 is always the average, with a standard deviation of 15 points. Scores follow a bell curve: about 68% of people fall between 85 and 115, and about 95% between 70 and 130.
IQ classification chart
| IQ score | Classification | How common |
|---|---|---|
| 145+ | Genius / near-genius | ~0.1% |
| 130–144 | Gifted / very superior | ~2% |
| 120–129 | Superior | ~7% |
| 110–119 | High average | ~16% |
| 90–109 | Average | ~50% |
| 80–89 | Low average | ~16% |
| 70–79 | Borderline | ~7% |
| Below 70 | Extremely low | ~2% |
What is a “genius” IQ?
There is no official cut-off, but a score of 140 and above is widely described as genius or near-genius level, and scores above 160 are extraordinarily rare. Keep in mind that IQ measures reasoning only — not creativity, drive or emotional intelligence, which shape real-world success just as much.
What percentile is my IQ?
A score of 100 puts you at the 50th percentile, 115 at the 84th, 130 at the 98th, and 145 near the 99.9th — meaning fewer than 1 in 1,000 people score that high.
Curious where you land? Try a free IQ test for adults or the classic IQ test for an instant estimate.
Frequently asked questions
What is the average IQ?
100, by design — about half of all people score between 90 and 109.
What is considered a high IQ?
Generally 130 or above, which is the top 2% of the population.
Online tests provide an estimate, 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