IQ guide
IQ scale and chart
Every number on the scale is a position, not a quantity. An IQ of 130 does not mean 30% more intelligence than 100. It means you scored higher than about 98 of every 100 people your age.
IQ score ranges
These are the descriptors used by the Wechsler scales, the most widely used clinical IQ tests.
| IQ range | Classification | Share of people |
|---|---|---|
| 130 and above | Extremely high (very superior) | 2.5% |
| 120–129 | Very high (superior) | 7.2% |
| 110–119 | High average | 16.6% |
| 90–109 | Average | 49.5% |
| 80–89 | Low average | 15.6% |
| 70–79 | Very low (borderline) | 6.5% |
| Below 70 | Extremely low | 2.1% |
IQ percentile chart
The second column shows the share of people who score lower. The last two columns convert the same position to tests that use a standard deviation of 16 (older Stanford-Binet editions) or 24 (Cattell).
| IQ (SD 15) | Higher than | Rarity | SD 16 | SD 24 |
|---|---|---|---|---|
| 70 | 2% | — | 68 | 52 |
| 80 | 9% | — | 79 | 68 |
| 85 | 16% | — | 84 | 76 |
| 90 | 25% | — | 89 | 84 |
| 100 | 50% | — | 100 | 100 |
| 110 | 75% | 1 in 4 | 111 | 116 |
| 115 | 84% | 1 in 6 | 116 | 124 |
| 120 | 91% | 1 in 11 | 121 | 132 |
| 125 | 95% | 1 in 21 | 127 | 140 |
| 130 | 98% | 1 in 44 | 132 | 148 |
| 135 | 99.0% | 1 in 100 | 137 | 156 |
| 140 | 99.6% | 1 in 260 | 143 | 164 |
| 145 | 99.9% | 1 in 740 | 148 | 172 |
| 150 | more than 99.9% | 1 in 2,300 | 153 | 180 |
| 160 | more than 99.9% | 1 in 31,600 | 164 | 196 |
How to read the scale
Every 15 points is one standard deviation. One step above average (115) beats about 84% of people. Two steps (130) beats about 98%. Three steps (145) beats about 99.9%. The tails thin fast: there are more than 100 times as many people at 115 or above than at 145 or above.
A single test score also carries measurement error. Clinical reports give a confidence band, typically about five points either side. Treat a score as a range, not a point.
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What is the IQ scale?
The IQ scale places the population average at 100 with a standard deviation of 15. Each 15 points is one standard deviation, so 115 is one step above average and 130 is two steps above.
What are the IQ score ranges?
On the Wechsler scale: 130 and above is extremely high, 120–129 very high, 110–119 high average, 90–109 average, 80–89 low average, 70–79 very low, and below 70 extremely low.
What percentage of people have an IQ over 130?
About 2.3% of people score above 130 on a standard-deviation-15 test, roughly one person in 44.
What is the highest score on the IQ scale?
Most clinical tests report up to about 160. Beyond that, the norm samples contain too few people to measure reliably, so claims of 200 or more are not scores from a standard modern test.
Why do some IQ charts use 16 or 24 points?
Older and some specialist tests use a different standard deviation. 130 on a 15-point scale equals 132 on a 16-point scale and 148 on a 24-point (Cattell) scale. The percentile, not the number, is what compares.
Scores on this page use the modern IQ scale: average 100, standard deviation 15 (Wechsler, Stanford-Binet 5). Online tests give estimates; only a supervised test by a qualified psychologist yields a diagnostic score.