The IQ scale
What your score means, from the classification chart to the exact percentile.
An IQ score isn't a grade out of 200: it's a position. Modern tests are normed so that the population average is 100 and the standard deviation is 15. An IQ of 115 therefore means “one standard deviation above average”, which is higher than about 84% of people.
IQ classification chart
The Wechsler scales, the most widely used in psychology, group scores into broad descriptive categories. The share of the population is the one predicted by the normal distribution.
| IQ | Category | Population |
|---|---|---|
| 130 and above | Very superior | 2% |
| 120 – 129 | Superior | 7% |
| 110 – 119 | High average | 17% |
| 90 – 109 | Average | 49% |
| 80 – 89 | Low average | 16% |
| 70 – 79 | Borderline | 6% |
| below 70 | Extremely low | 2% |
IQ percentile for every score
The percentile tells you the share of the population scoring below you. It's the most intuitive way to read an IQ score.
| IQ | Higher than |
|---|---|
| 70 | 2% |
| 75 | 5% |
| 80 | 9% |
| 85 | 16% |
| 90 | 25% |
| 95 | 37% |
| 100 | 50% |
| 105 | 63% |
| 110 | 75% |
| 115 | 84% |
| 120 | 91% |
| 125 | 95% |
| 130 | 98% |
| 135 | 99.0% |
| 140 | 99.6% |
| 145 | 99.9% |
What is the average IQ?
By definition, 100. About two people out of three have an IQ between 85 and 115, and 95% between 70 and 130. Being “average” is by far the most common case, and there's nothing negative about it.
What IQ counts as gifted?
The usual threshold is 130, two standard deviations above the mean, which is roughly the top 2% of the population. It's also the cut-off used by high-IQ societies such as Mensa (98th percentile). Only a full assessment by a psychologist (WAIS or WISC) can establish it, never an online test.
What the scale doesn't tell you
- A score always comes with a margin of error: think of a range, not an exact number.
- IQ measures certain kinds of reasoning. It doesn't capture creativity, social skills or a person's worth.
- Norms age: during the 20th century, raw scores rose by about 3 points per decade (the Flynn effect), which is why tests are regularly re-normed.