George Frideric HandelComposer
Cox rated him 155 for ages 17 to 26, the same as this page's score. Cox's childhood rating for him was 145.
What does an IQ of 155 mean?
An IQ of 155 is higher than about 99.99% of people: roughly 1 in 8,139 scores this high or above. It is the score historians of intelligence associate with Mozart, Dickens and Handel, and the figure most often attached to Elon Musk.
99.987thpercentile
1 in 8,139score 155 or higher
Highly giftedlevel of giftedness
155IQ scoreTop 0.012%
155 on the IQ bell curve
At 55 points above the mean of 100 (3.67 standard deviations), 155 sits where the curve has almost flattened onto the axis. Only 0.012% of people score here or higher; on the left chart that group is the barely visible orange edge.
155 sits three and two thirds standard deviations above average, where the curve is barely a thousandth of its height at the peak.
Reading an IQ of 155
155 is the number with the most famous company, and almost all of it is borrowed. Catharine Cox's 1926 study rated Mozart, Charles Dickens and George Frideric Handel at 155 for their late teens and early twenties, using letters, school records and early works. Elon Musk's widely quoted 155, by contrast, has no source at all.
The real 155 is shared by about one million people worldwide. In the United States, that would be around 42,000; in the United Kingdom, about 8,500. It is also the upper end of the "optimum" range of 125 to 155 that the psychologist Leta Hollingworth described in 1942.
How many people have an IQ of 155?
How big a group do you need before someone in it is likely to score 155? About 8,139 people. Watch the crowd grow to that size.
A crowd of 8,139 people
8,139
One dot per person, and on average only one of them, shown in orange, scores 155 or more.
People scoring 155 or higher, by population
| Worldwide (8.2 billion people) | about 1,010,000 |
| India | about 180,000 |
| United States | about 42,000 |
| United Kingdom | about 8,540 |
| Canada | about 5,120 |
| Australia | about 3,390 |
Population: World Bank, total population, 2025. Counts assume the same bell curve in every country and are rounded. Real tests can't sort people this finely, as the next sections explain.
Which high-IQ societies accept an IQ of 155?
Entry to a high-IQ society depends on a percentile, which each one turns into a score per accepted test. Measured under supervision, 155 meets 4 of the 6 bars; the next, Prometheus Society, needs about 160.
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MensaTop 2% (98th percentile) on an approved, supervised test130met
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IntertelTop 1% (99th percentile); lists a Wechsler full-scale IQ of 135135met
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Triple Nine Society99.9th percentile; lists a WAIS full-scale IQ of 146146met
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International Society for Philosophical Enquiry99.9th percentile; lists a WAIS-III or WAIS-IV full-scale IQ of 146146met
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Prometheus Society1 in 30,000 (99.997th percentile), four standard deviations above average160not met
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Mega SocietyOne in a million, beyond the range of standard tests171not met
Scores for Mensa, Intertel, Triple Nine and ISPE are the Wechsler figures those societies list or that match their percentile. Prometheus and Mega give only a rarity; the scores shown are the matching points on the standard scale. Prometheus says no test currently being given is approved for its entry. Online test results are not accepted by any of them.
Can an IQ test measure 155?
Each bar is the highest full-scale IQ a test can report. The adult Wechsler test and the Stanford-Binet both stop at 160, so 155 is still inside their range.
Why so uncertain? Because a test compares you with its norm sample, and the WAIS-IV sample had 2,200 adults. The bell curve predicts about 0.27 of them at 155 or higher, less than one person, so the scoring at this level comes from the curve's shape rather than from real high scorers.
Add the usual margin of error, about five points either way, and a result of 155 really means somewhere near 150 to 160. No online test, ours included, can pin down a score this high. What online tests can and can't tell you.
Sources: WAIS-IV range and norm sample from Canivez (2010), Mental Measurements Yearbook review; Stanford-Binet 5 and its Extended IQ from PRO-ED; WISC-V extended norms from Pearson Technical Report #6 (2019). Striped bars are extended scales, used only when a person hits the normal ceiling.
Converting an IQ of 155 between scales
The number attached to a result depends on the scale's standard deviation. Near 155, switching scales can add or remove dozens of points for exactly the same rank.
155standard scale (SD 15), used by Wechsler tests and on this page
159older Stanford-Binet scale (SD 16)
188Cattell scale (SD 24), used by some older and online tests
So a "155" isn't always a 155. On the Cattell scale it corresponds to about 134 on the standard scale; on an SD 16 scale, about 152. Why IQ scales differ.
Who has been rated near an IQ of 155?
Catharine Cox's 1926 study is the source of nearly every historical "IQ". She estimated each person's score from records of their early life, once for childhood and once for ages 17 to 26. None of them sat a test.
Charles DickensNovelist
Cox rated him 155 for ages 17 to 26, the same as this page's score. Cox's childhood rating for him was 145.
Wolfgang Amadeus MozartComposer
Cox rated him 155 for ages 17 to 26, the same as this page's score. Cox's childhood rating for him was 150.
Source: Cox, C. M. (1926), Genetic Studies of Genius, Vol. II: The Early Mental Traits of Three Hundred Geniuses, Stanford University Press. Cox stressed that thin records pull estimates down. Read more in where the historical genius IQ estimates came from.
Who is said to have a 155 IQ?
These names are often given an IQ at or close to 155. Not one of the figures is backed by a published test result.
Elon Musk
No test result has ever been published. The figure circulates on websites without a source.
SS
154Reported, no test shown
Sharon Stone
Printed in the introduction to a 1992 Playboy interview, not in her own words. Mensa said in 2002 she had never been a member.
LK
154No evidence of a test
Lisa Kudrow
The figure traces only to online discussion threads.
Sources for every claim are listed in our celebrity IQ list.
How Cox estimated historical IQs near 155
Cox and her fellow raters read detailed records of each person's youth and compared them with what children of known IQ could do at the same ages. Mozart, for example, was composing and performing across Europe as a child. Each person received two ratings: one for childhood and one for ages 17 to 26. Mozart's were 150 and 155; Dickens' and Handel's were 145 and 155.
Cox knew sparse records pulled her estimates down, so she also calculated corrected group averages, which raised the typical childhood figure from about 135 to 155. That is one reason the same people appear with much higher numbers on internet lists. The uncorrected ratings shown on this page are the ones she reported for each person.
Source: Cox, C. M. (1926), Genetic Studies of Genius, Vol. II, Stanford University Press.
What does an IQ of 155 mean?
A score of 155 means a level of reasoning matched by about one person in eight thousand. It is "highly gifted" on gifted-education levels and on the edge of what standard tests can reliably separate. As with any score this high, it describes performance on a test, not a person's worth or their future.
Where 155 falls among the levels of giftedness
115–129Mildly gifted
130–144Moderately gifted
145–159Highly gifted
160–179Exceptionally gifted
180+Profoundly gifted
Levels and ranges from Gross, M. U. M. (2000), "Exceptionally and Profoundly Gifted Students: An Underserved Population", Understanding Our Gifted. They are a guide for education, not a ranking of people.
How far 155 is from other milestones
25 points above the usual Mensa level (130)a score of 155 is about 185 times rarer than 130
9 points above the Triple Nine and ISPE bar (146)a score of 155 is about 8.8 times rarer than 146
5 points below the ceiling of most professional tests (160)reaching 160 is about 4 times rarer than 155
3.67 standard deviations above averageaverage is 100 and one standard deviation is 15 points
IQ 155 compared with nearby scores
| IQ | Percentile | Rarity | Level |
|---|---|---|---|
| 151 | 99.966th | 1 in 2,968 | Highly gifted |
| 153 | 99.979th | 1 in 4,874 | Highly gifted |
| 155 | 99.987th | 1 in 8,139 | Highly gifted |
| 157 | 99.9927th | 1 in 13,822 | Highly gifted |
| 159 | 99.9958th | 1 in 23,873 | Highly gifted |
Your questions about a 155 IQ
Is 155 a high IQ?
Yes. 155 is a very high IQ: about 1 person in 8,139 scores this high or higher, which puts it at the 99.987th percentile. It is above the 130 that most definitions use for a high IQ, and at or above the 146 used by the Triple Nine Society for its 99.9th percentile entry.
How rare is an IQ of 155?
About 1 person in 8,139 scores 155 or higher, on the standard bell curve. Across the world's population of about 8.2 billion, that would be roughly 1,010,000 people.
Is an IQ of 155 good?
Yes, by any measure. 155 is higher than about 99.99% of people. Remember that a score this high needs a supervised professional test to be confirmed, and that it describes reasoning on a test, not every kind of talent.
Can you join Mensa with an IQ of 155?
Yes. Mensa accepts the top 2% on an approved, supervised test, which is about 130 on the standard scale. A supervised 155 would also meet the bar for Intertel, Triple Nine Society and International Society for Philosophical Enquiry. Online test results are not accepted.
What does 155 IQ mean?
It means a result 55 points, or 3.67 standard deviations, above the average for your age. On the levels used by gifted education researchers, 155 is highly gifted (145–159).
Did Mozart have an IQ of 155?
Not from a test. In 1926 the psychologist Catharine Cox estimated his IQ from records of his early life at about 150 for childhood and 155 for ages 17 to 26. These are historical estimates, and Cox warned that they depend on how much was written down.
Related: what counts as a good IQ score, the highest IQ in the world, famous people's IQs and the full IQ scale and range chart.
An IQ test arrives at a score like 155 by combining several kinds of task. Learn more about fluid vs crystallized intelligence, abstract reasoning, spatial reasoning, verbal reasoning and processing speed, or try the free pattern recognition test.
Many famous IQ figures are guesses. See what is really known about Stephen Hawking's IQ, Bill Gates' IQ, Elon Musk's IQ, Garry Kasparov's IQ, Terence Tao's IQ, Einstein's IQ, Isaac Newton's IQ and Nikola Tesla's IQ.
Curious where you'd land?
Try the free Assessivo IQ test: 36 questions, about 25 minutes, and an estimated score up to 145. Confirming a result as high as 155 needs a supervised professional test.
Take the free IQ testPortraits are pencil-style sketches by Assessivo, based on: George Frideric Handel after a portrait attributed to Balthasar Denner (about 1727), public domain. Charles Dickens after a photograph by Jeremiah Gurney (1867), public domain. Wolfgang Amadeus Mozart after Barbara Krafft (1819), public domain. Elon Musk sketch adapted from a photo by Gage Skidmore, CC BY-SA 4.0.