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Who has the IQ of 300?

An IQ of 300 is exceptionally rare. In fact, there are very few people in recorded history who are claimed to have an IQ this high. An IQ score this elevated signifies profound cognitive ability that only a handful of people in the world possess. So who has demonstrated an IQ of 300? Let’s investigate some of the people who have been purported to reach this stratospheric level of intelligence.

Understanding IQ

Before looking at individuals with IQs of 300, it’s helpful to understand what exactly IQ measures. IQ stands for intelligence quotient and it is a score derived from standardized tests designed to assess human intelligence and cognitive ability.

The most widely used IQ tests today are the Stanford-Binet Intelligence Scale and the Wechsler Adult Intelligence Scale (WAIS). On both these tests, 100 is set as the median score, with a standard deviation of 15. This means that about 68% of people score between 85 and 115. 130 is considered gifted, 145 is considered genius, and anything over 170 is considered revolutionary genius.

An IQ of 300 is more than 10 standard deviations above the mean and implies cognitive functioning and intelligence that is extraordinarily rare even among the most brilliant minds. Only a few people in history are claimed to have reached this level.

William James Sidis

One of the first people to be attributed an IQ of 300 is William James Sidis (1898-1944). Sidis was an American child prodigy in the early 20th century.

His parents, both educated Russian Jewish immigrants, deliberately cultivated Sidis’ brilliance from a very early age. Sidis was claimed to have been able to read the New York Times by age 18 months. By age 5, he was proficient in Latin, Greek, French, Russian, German, and Hebrew. At age 11, he enrolled in Harvard University and graduated cum laude at age 16.

Sidis was called the “smartest man who ever lived” in a 1921 New York Times article. Biographers and journalists estimated his IQ to be between 250 and 300 based on his exceptional accomplishments as a child prodigy. However, these estimates were speculative as Sidis never actually sat a standardized IQ test.

Despite his promising early accomplishments, Sidis later sought anonymity and took on more mundane jobs like bookkeeper and clerk. He died relatively poor at age 46 following a cerebral hemorrhage.

Kim Ung-Yong

Kim Ung-Yong (born 1962) is a Korean former child prodigy who holds the Guinness World Record for highest IQ at 210.

Kim Ung-Yong was a guest physics student at Hanyang University by age 3. He was able to read Korean, Japanese, English, German, and many other languages by age 4. By age 8, Kim was working as a university lecturer in physics. His IQ was measured to be over 210.

Some biographies of Kim claim that his IQ scores reached as high as 300, but these claims are unsubstantiated. Kim’s proven IQ of 210 is still one of the highest ever recorded.

Kim Ung-Yong earned his PhD in physics at age 15 and worked as a university professor before being recruited by NASA. Later in life, Kim returned to South Korea and taught at universities there. He stated that his childhood was dominated by studying and he now wishes to live a more normal life.

Christopher Langan

Christopher Langan (born 1952) has been dubbed “the smartest man in America” with an IQ reported between 195 and 210. He has claimed that his IQ is substantially higher.

Langan achieved a perfect SAT score while only in high school. He dropped out of college after concluding that its pace was holding him back. Langan has mastered dozens of disciplines from mathematics and physics to philosophy and music.

Some media reports in the 1990s claimed that Langan’s IQ was measured at over 300. However, while Langan clearly possesses an exceptionally high intelligence, there is no published evidence that he has actually tested at this level.

Langan has developed a philosophy and framework he calls the “Cognitive-Theoretic Model of the Universe” which synthesizes physics, math, philosophy, spirituality and other fields. He has offered consultancy services in problem solving and intelligence testing.

Marilyn vos Savant

Marilyn vos Savant (born 1946) has been listed in the Guinness Book of World Records for the highest IQ at 228.

Vos Savant took the Stanford-Binet test at age 10 and scored a mental age of 22 years and 10 months old, yielding a 228 ratio IQ score. She was entered in the Guinness Book of World Records in 1985 as having the highest IQ ever recorded.

However, Marilyn vos Savant has not claimed an IQ of 300. There is no evidence she re-tested as an adult to confirm or update her childhood score. All credible reports list vos Savant’s IQ as 228 rather than 300.

Vos Savant has monetized her reputation as having the “world’s highest IQ” through books, a newspaper column, and other media. She is known for her responses to reader puzzles and questions on logic, probability, and other topics.

Garry Kasparov

Garry Kasparov (born 1963) is considered by many to be the greatest chess player of all time. His IQ has been reported as high as 194 by some biographers. Kasparov himself has estimated his IQ to be around 135.

Kasparov became the youngest ever undisputed World Chess Champion in 1985 at age 22. He held the number-one position for 255 months, the longest of any player. Kasparov retired from professional chess in 2005 after a long dominance of the game.

Some early reports claimed Kasparov’s IQ was over 300. However, these reports were unfounded. Kasparov himself has published his tested IQ as 135, though others argue it could be higher based on his remarkable chess accomplishments. An IQ of 300 has no basis.

Kasparov is widely regarded to have pushed the game of chess to new levels. Since retiring, he has taken up politics and writing. He is considered by many the greatest chess player ever, but does not have a recorded IQ near 300.

Philip Emeagwali

Philip Emeagwali (born 1954) is a Nigerian computer scientist who has been hailed as the “Bill Gates of Africa.” He holds three Master’s degrees in mathematics, environmental and marine engineering.

In 1989, Emeagwali won the Gordon Bell Prize for an oil reservoir modeling calculation performed using a novel mathematical formula he devised. Some biographies of Emeagwali claim that he has an IQ of 300.

However, while Emeagwali clearly has high intellectual abilities, especially in mathematics, there is no evidence he has ever tested at this level. He has mainly focused his career on computing and petroleum engineering rather than cognitive testing. An IQ of 300 is likely an exaggeration of his abilities.

Other Claims of Extreme IQs

A few other individuals through history have been claimed to have extraordinary IQs of 300 or higher, though these claims are generally not substantiated by much evidence. For example:

– Sir Andrew Cohen is reported by some sources to have an IQ of 300, but the original basis for this claim is unclear.

– Jaxon Cota, a child chess prodigy, was attributed an IQ of 300 in some media reports, but this seems unlikely given his young age.

– Explorer and information theorist Nira Cain has been listed by some sources as having an IQ “over 300”, but this has not been verified by testing.

While the people mentioned above do have remarkably high intelligence, confirmed IQ scores near 300 remain elusive. Some individuals clearly have extremely rare cognitive abilities, but quantifying this accurately with IQ tests remains challenging. An IQ of 300 or higher implies intellectual functions that are not fully understood.

Measuring Extreme IQs

Are IQ tests even capable of accurately measuring super-high IQs? Most tests have ceilings past which they cannot differentiate exceptional cognitive ability.

For example, the most commonly used WAIS test has a ceiling of 160 (at the 99.997th percentile). The extended Stanford-Binet scales up to 200. Beyond these ceilings, the tests cannot give meaningful results.

Specialized IQ tests have been developed for measuring highly gifted individuals. Examples include the Mega Test and Titan Test developed by Ronald Hoeflin, which scale up to IQ 400.

On these kinds of tests, scores above 250 become highly speculative as the tests sample questions and problem-solving capabilities outside most human experience. Verifying IQs above 300 is problematic due to the limitations of testing instruments and the tiny sample of people at this level.

Correlation with Accomplishment

Ultimately, an extraordinary IQ score in itself may not guarantee equally extraordinary real-world achievement. Beyond a certain threshold, factors like determination, opportunity, resources, stability, and sheer luck play a role in what high-IQ individuals actually accomplish.

Many people with proven stratospheric IQs, like Nobel Prize winners and other eminent scientists, have made breakthrough contributions to human knowledge. However, others with comparable high IQ scores died in poverty and obscurity or underachieved their potential for other reasons.

While IQ tests can indicate exceptional fluid intelligence and problem-solving potential, they cannot measure character traits like persistence, resilience, social skills, leadership talent, and emotional intelligence, which also contribute heavily to accomplishment. IQ is not destiny.

Distribution of Ultra-High IQs

Just how rare are IQ scores over 300, if they exist at all?

130 IQ is considered “gifted” and includes about 2.5% of the population. 145 IQ reaches “genius” territory and includes 0.1% of people. 170 IQ is labeled “revolutionary genius” and likely includes no more than a few thousand living individuals on Earth.

Based on the normal distribution, the probability of having an IQ over 300, if measurable, is vanishingly small. Fewer than 1 in 1 billion people are estimated to fall into this range, if anyone actually does. This makes evaluating claims of IQs over 300 exceptionally difficult given the tiny population sample size.

Until more rigorous testing methods for high ranges are developed, claims of 300 or higher IQ scores remain speculative and improbable. While the human brain has remarkable potential that science does not fully understand, IQ scores above 250 currently lack solid evidential basis.


In summary, while several people throughout history have been attributed IQ scores of 300 or higher, these claims are generally unsubstantiated and lack rigorous testing proof. The individuals mentioned are clearly exceptionally intelligent, but actual IQs approaching 300 are currently unverifiable.

Measuring super-high IQs remains challenging due to limitations of testing instruments, the extreme rarity of the top range, and lack of research on validating these scores.

While the possibility of IQs over 300 can’t be ruled out, evidence for them is weak. Until more research happens, IQ scores above 250 should be interpreted very skeptically as their meaningfulness is still in question. While some people do have exceptionally high cognitive potential, accurately quantifying an IQ of 300 remains elusive.