IQ 155: what it means, percentile and how rare it is
An IQ score of 155 is higher than about 99.988% of people, which puts it in the 99.988th percentile. Roughly 1 in 8,140 people score higher than 155. On the WISC-V it is classified as Extremely High.
- Percentile
- 99.988th
- Higher than
- 99.988%
- People scoring higher
- 1 in 8,140
- WISC-V classification
- Extremely High
What does an IQ of 155 mean?
- 155 is above the top-2% line Mensa uses for admission (130 on the Wechsler scales), if it comes from an approved, supervised test.
Scores from 145 to 159 are three to four standard deviations above the mean: about 1 in 740 people score above 145 and about 1 in 8,100 above 155. The Stanford-Binet 5 calls this range "very gifted or highly advanced"; on the WISC-V it is part of the Extremely High range that starts at 130.
People in this range typically learn abstract material very quickly and can handle complex problems far beyond what is typical for their age. Children here are often accelerated at school or placed in specialist gifted programmes.
At this level tests begin to run out of difficult questions, so measurement error grows. Two good tests can easily disagree by 5 to 10 points, and a high score is a strong sign of exceptional reasoning rather than an exact rank.
IQ 155 on other scales and tests
Different tests spread scores differently. The same rank as an IQ of 155 on an SD-15 test gives these numbers elsewhere:
| Scale | Equivalent score | Classification |
|---|---|---|
| SD 15: WISC-V, WAIS, Stanford-Binet 5 | 155 | Extremely High |
| WAIS-IV (older label) | 155 | Very Superior |
| Stanford-Binet 5 | 155 | Very gifted or highly advanced |
| SD 16: older Stanford-Binet, Cattell Culture Fair | 159 | – |
| SD 24: Cattell III B | 188 | – |
How precise is an IQ score of 155?
No test measures IQ exactly. On individually administered tests such as the WAIS, the full-scale score comes with a 95% confidence interval of roughly ±5 points, so a result of 155 is best read as "probably somewhere between 150 and 160". Scores can also shift a few points between different tests or after a few years.
Precision also drops near the top of the scale. Standard WAIS and WISC norms end at 160, and a norming sample of a few thousand people contains almost nobody at these levels, so scores this high are estimates built on very few cases.
Online tests, including ours, are self-assessments. They are useful for curiosity and practice, but they are not a substitute for an assessment by a psychologist.
IQ scores near 155
| IQ score | Percentile | Higher than | WISC-V classification |
|---|---|---|---|
| 150 | 99.957th | 99.957% | Extremely High |
| 151 | 99.966th | 99.966% | Extremely High |
| 152 | 99.974th | 99.974% | Extremely High |
| 153 | 99.979th | 99.979% | Extremely High |
| 154 | 99.984th | 99.984% | Extremely High |
| 155 | 99.988th | 99.988% | Extremely High |
| 156 | 99.9906th | 99.9906% | Extremely High |
| 157 | 99.9928th | 99.9928% | Extremely High |
| 158 | 99.9945th | 99.9945% | Extremely High |
| 159 | 99.9958th | 99.9958% | Extremely High |
| 160 | 99.9968th | 99.9968% | Extremely High |
Check another IQ score
For example 98 for the top 2%.
- Percentile
- 99.988th
- Higher than
- 99.988%
- People scoring higher
- 1 in 8,140
- Classification (WISC-V)
- Extremely High
IQ 155: frequently asked questions
Is an IQ of 155 good?+
Yes, exceptionally so. An IQ of 155 is higher than about 99.988% of people. It sits in the range the Stanford-Binet 5 calls very gifted, well above Mensa's top-2% line.
What percentile is an IQ of 155?+
An IQ of 155 is in the 99.988th percentile on a scale with mean 100 and standard deviation 15. It is higher than about 99.988% of people and lower than about 0.012%.
How rare is an IQ of 155?+
Roughly 1 in 8,140 people score higher than 155. Out of a million people, you would expect about 123 to score higher.
Is 155 a genius IQ?+
"Genius" is not a scientific category and no test uses it, but 155 is the kind of score popular articles mean by it: it is higher than about 99.988% of people. Achievement still depends on far more than IQ, including knowledge, effort, creativity and opportunity.