Top 10 People With the Highest IQ in the World (2026)

If you Google “highest IQ in the world,” you’ll see a list. 228. 230. 250. 276. Sometimes you’ll even see 300.

These numbers seem precise. Most of them are not.

Some are based on actual tests given to children many years ago, on a scoring method psychologists no longer use. Some are estimates worked backward from a child’s exam results. Some were reported secondhand, after the person’s death. And at least one appears to have been inflated by changing the math on a lower score.

The people behind them are still remarkable. But a fair list should label the scores that were measured, label the scores that were estimated and label the scores that simply can’t be verified.

That’s this list.

Every entry below has a plain label, and the ranking favors real evidence over flashy scores. This guide looks at the people with the highest IQ in the world, where all those famous IQ scores came from, and why two IQ scores can mean very different things.

How We Ranked the People With the Highest IQ

Rankings were based on two factors, in this order: how strong the evidence behind the IQ score is, and then the number itself. A score from an administered, supervised test outranks a bigger number that nobody can trace.

Each person gets one of three labels:

• ✔ Tested: the figure comes from a named, administered intelligence test.
• ✔ Estimated: the figure was calculated or inferred from other evidence, such as exam scores, by researchers or journalists.
• ✔ Claimed or reported: the figure circulates in the media or comes from the person or their circle, with no published test behind it.

Why IQ Scales Do Not Match

Most modern IQ tests, including the current Wechsler and Stanford-Binet tests, set the average at 100 with a standard deviation (SD) of 15 points. Some older tests, and many online “high-range” tests, use an SD of 16 or even 24. That means the exact same performance can translate into different IQ scores.

Mensa points out that a score of 132 on one IQ test can be equivalent to 148 on another. That’s why it sets its qualifying bar at the 98th percentile rather than at a single number (see Mensa’s testing FAQ).

Take a score of 198 on an SD 15 scale. That puts someone roughly 6.5 standard deviations above average. The same rarity would read as about 205 on an SD 16 scale, and a whopping 257 on an SD 24 scale.

Why Childhood Scores Run So High

When IQ tests were first developed, they used a “ratio IQ.” You divided a child’s “mental age,” as measured by the test, by their actual age, then multiplied by 100. A 10-year-old who performs like a typical 23-year-old gets a ratio IQ of 230.

Today’s tests use a “deviation IQ.” This system, introduced by David Wechsler in 1939, measures how far your performance sits from the average of people your own age. Ratio scores for gifted children often land far above anything a modern adult test can produce, and they don’t translate directly into modern scores.

Why No Test Can Crown a Winner

Standard IQ tests run out of hard questions at around 160, so it’s difficult to measure much higher scores by any conventional method. That’s why Guinness World Records eliminated its “Highest IQ” category back in 1990. No official world record holder exists today.

Highest IQ in the World at a Glance (2026)

Top 10 People With the Highest IQ in the World (2026)

Here are the ten names that come up most in the highest IQ debate, along with the evidence in each case.

1. Marilyn vos Savant

Marilyn vos Savant holds the best-documented claim to the highest IQ ever recorded, which is why she’s at the top of this list. She was born on August 11, 1946, in St. Louis, Missouri. In September 1956, at age 10, she took the 1937 revision of the Stanford-Binet test. That exam pegged her mental age at 22 years and 10 months, which works out to a ratio IQ of 228.

Guinness World Records listed vos Savant under “Highest IQ” in the late 1980s, until it removed the category in 1990. As an adult, she scored 46 out of 48 on Ronald Hoeflin’s Mega Test in the mid-1980s. Hoeflin translated that into 186 on an SD 16 scale. Psychologists have since criticized the Mega Test’s design and scoring.

Her Guinness listing caught the public’s attention. She started her “Ask Marilyn” column in Parade magazine in 1986. In 1990, her solution to the Monty Hall probability puzzle brought in about 10,000 letters, many from readers adamant that she was wrong. She wasn’t.

• ✔ Status: Tested (childhood ratio IQ; adult Mega Test score)
• ✔ Known for: “Ask Marilyn,” the Monty Hall problem

2. Kim Ung-yong

Kim Ung-yong was born on March 8, 1962, in Seoul, and became one of the best-known child prodigies of the 20th century. Guinness World Records once featured him under “Highest IQ” with a score of 210. The figure comes from childhood testing in the ratio-IQ era. The test details have never been published, so the score can’t be checked against modern standards.

His brilliance drew attention around the world at a young age. At 5, he appeared on Japan’s Fuji Television solving differential equations. Popular media has also reported that NASA hired him as a child, but that claim has never been confirmed. Kim’s own family has said American reports of his time overseas were exaggerated, and his mother said he only audited courses at the University of Colorado for a brief time.

Kim chose a more ordinary life as he grew up. He earned his PhD in civil engineering from Chungbuk National University and has been a professor at Shinhan University since 2014.

• ✔ Status: Tested in childhood; method and records not public
• ✔ Known for: Childhood mathematics, choosing an ordinary career

3. Terence Tao

Terence Tao’s name comes up all the time in debates about the smartest person alive. His IQ number was never produced by a formal IQ test, but his body of work backs up the reputation. Tao was born in Adelaide, Australia, in 1975. At age 8, he scored 760 out of 800 on the SAT math section. Researchers Julian Stanley and Miraca Gross used his childhood results to estimate an IQ of roughly 220 to 230.

Tao himself has downplayed those numbers. He has written that such estimates are “extremely noisy at these scales” and has suggested that simply “greater than 175” is a more realistic description.

His achievements need no estimating. He won medals at the International Mathematical Olympiad at ages 10, 11 and 12, taking gold in 1988, just before his 13th birthday. By 20, he had completed his PhD at Princeton. By 24, he was a full professor at UCLA. He won the Fields Medal and a MacArthur Fellowship in 2006.

• ✔ Status: Estimated from childhood test data
• ✔ Known for: Harmonic analysis, number theory, the Fields Medal

4. Christopher Hirata

Christopher Hirata’s IQ is typically listed as about 225. The problem is that no published source explains where that number came from. His academic record, on the other hand, is well documented. Hirata was born on November 30, 1982, in Michigan. In 1996, at age 13, he won a gold medal at the International Physics Olympiad.

He started at Caltech at 14 and graduated with a physics degree in 2001, at 18. According to Princeton’s student newspaper, he worked on NASA-related research into colonizing Mars at 16. He then earned his PhD in astrophysics at Princeton in 2005.

Hirata is now a professor of physics at Ohio State University’s Center for Cosmology and AstroParticle Physics. His research covers dark energy, gravitational lensing and the early universe, and he has worked on NASA’s Nancy Grace Roman Space Telescope. He won the New Horizons in Physics Prize in 2018.

• ✔ Status: Reported; source of the 225 figure unknown
• ✔ Known for: Cosmology, the Physics Olympiad gold at 13

5. Sho Yano

Sho Yano’s IQ is often listed as about 200, a number you’ll mostly see in articles about his childhood. No test details have been published. What is documented is a pace of learning that very few people have matched.

Yano was born in 1990 in the United States. At age 8, he scored 1500 out of 1600 on the SAT. He started college at Loyola University Chicago at 9, and in 2003, at 11, he was accepted to the University of Chicago’s Pritzker School of Medicine.

He didn’t just attend medical school. Along the way, he completed doctoral research, earning his PhD in molecular genetics and cell biology in 2009, at 18. He then finished his MD in 2012, at 21, making him the youngest person to graduate from the University of Chicago’s medical program. After that, he began training in pediatric neurology.

• ✔ Status: Reported in media; no test published
• ✔ Known for: PhD at 18, MD at 21

6. Evangelos Katsioulis

Greek psychiatrist Evangelos Katsioulis shows why lists like this need to name their scale. The World Genius Directory has reported his IQ as 198 on an SD 15 scale and 205 on an SD 16 scale. That’s the same result expressed two different ways, not two separate accomplishments. Lists that print one number and not the other are simply using different scales.

His scores come from high-range IQ tests, often taken at home without supervision, and he has reportedly taken more than 30 of them. Psychologists regard these tests with caution because they are not normed the way clinical IQ tests are.

Beyond IQ testing, Katsioulis studied medicine and psychiatry and has earned further degrees in philosophy, medical research technology and psychopharmacology. He founded the World Intelligence Network, a parent organization for high-IQ societies, in 2001 and has since founded several other groups.

• ✔ Status: Reported; unsupervised high-range tests
• ✔ Known for: Psychiatry, the World Intelligence Network

7. Christopher Langan

Christopher Langan is often called the smartest man in America, but his best-known number is an estimate. The figure of 195 originated in a 1999 Esquire magazine profile and was later repeated in Malcolm Gladwell’s book Outliers.

Born in 1952 in San Francisco, Langan attended Reed College and Montana State University before leaving without a degree. He then spent about 20 years working as a bouncer.

In 1999, a neuropsychologist tested Langan for ABC’s 20/20, and the program described his results as “off the charts.” No exact score was published, because the test hit its ceiling. His higher claims rest on Hoeflin’s Mega Test, an untimed mail-in exam taken with no supervision. In 2008, he won $250,000 on NBC’s game show 1 vs. 100.

Langan is best known for his Cognitive-Theoretic Model of the Universe (CTMU), a self-published theory of mind and reality. It has not gained acceptance in mainstream physics or philosophy, and some of his public opinions have drawn strong criticism.

• ✔ Status: Estimated; formal test reached its ceiling
• ✔ Known for: The CTMU, his unusual career path

8. Rick Rosner

Rick Rosner is another name that pops up on these lists, often with an IQ of 192. No published test produced that number. His performance on Ronald Hoeflin’s high-range Mega Test is on record, though: he reportedly scored 44 out of 48 in 1985 to gain admission to the Mega Society, then 47 out of 48 when he retook the test in 1991. A 2020 academic analysis concluded that the official scores from Hoeflin’s tests were too high.

Rosner was born on May 2, 1960, and has written for several well-known TV shows. He began writing for MTV’s quiz show Remote Control in 1987. Later credits include The Man Show, Crank Yankers and Jimmy Kimmel Live!, and he has been nominated for an Emmy Award.

His résumé also includes jobs you won’t find on most TV writers’ CVs. He says he has worked as a stripper, bouncer, nude model and roller-skating waiter. In 2000, he sued Who Wants to Be a Millionaire after losing on a question about the world’s highest capital city.

• ✔ Status: Reported; high-range test scores only
• ✔ Known for: TV comedy writing, a colorful life story

9. William James Sidis

William James Sidis often appears at the top of “highest IQ ever” lists with a score between 250 and 300. The problem is that there is no record he ever took an IQ test.

The figure comes from Abraham Sperling’s 1946 book Psychology for the Millions. Sperling relayed a claim from Sidis’s sister, Helena, that a psychologist had put his IQ in that range. No test, date or examiner is named.

The accomplishments on record are impressive. Born on April 1, 1898, in Boston, Sidis enrolled at Harvard in 1909, at age 11. In January 1910, he lectured the Harvard Mathematical Club on four-dimensional bodies. He graduated cum laude in 1914, at 16.

Sidis faded from public view after college. He held clerical jobs and published under pseudonyms. He sued The New Yorker for invasion of privacy but lost in 1940. He died in 1944, at age 46.

• ✔ Status: Claimed (secondhand, never documented)
• ✔ Known for: Harvard at 11, a famously private later life

10. YoungHoon Kim

South Korea’s YoungHoon Kim is the person behind the 276 score now found at the top of many online lists. He promotes himself as having the highest IQ in the world. Guinness World Records has not verified his score, and no independent psychologist has either.

In July 2025, Vice published an investigation into Kim’s claim. It reported that the 276 score probably came from a 210 on an obscure test normed on only 32 people, then rescaled using an SD of 24 instead of 15. On a standard SD 15 scale, the same result doesn’t come close to 276. Experts quoted by Vice put his likely IQ at around 160 to 175.

Journalists have also questioned groups that claim to endorse Kim. Swiss newspaper Blick reported in January 2025 that Paul Cooijmans, founder of the original Giga Society, says Kim has used the society’s name without permission since 2021.

Kim is here because people will see his number repeated across the internet. He ranks last because the claims behind his number are the weakest of anyone on this list.

• ✔ Status: Claimed and disputed
• ✔ Known for: The viral 276 claim

How to Read Any “Highest IQ” Claim

Before you trust a number on a highest IQ list, check four things.

Was There a Real Test?

Ask which test produced the score, who gave it and when. If an article cannot name a test, the number is an estimate or a claim.

Which Scale Was Used?

A score without its standard deviation is incomplete. Converting between SD 15, 16 and 24 can move a number by dozens of points.

Was It Taken as a Child?

Childhood ratio scores, like vos Savant’s 228, measure how far ahead of their age a child was. They are not the same as an adult deviation score.

Was It Supervised?

Untimed, unsupervised online or mail-in tests are popular in high-IQ societies, but psychologists do not treat them like clinical tests.

FAQs

Who has the highest IQ in the world right now?

There is no official answer. Guinness retired the category in 1990. Among living people, Marilyn vos Savant has the best-documented high score, 228, though it is a childhood ratio score. Terence Tao is often named the smartest person alive, but his 220 to 230 figure is an estimate.

Is YoungHoon Kim’s IQ of 276 real?

It has not been verified. Reporting by Vice suggests the figure came from rescaling a 210 score on a non-standard test using an SD of 24, and experts estimated his IQ at about 160 to 175.

What was Einstein’s IQ?

Nobody knows. Albert Einstein never took an IQ test. The commonly quoted figure of about 160 is a later guess. The same is true of Stephen Hawking.

What about Garry Kasparov’s 190?

That number has no known source. When Der Spiegel tested Kasparov in 1987, he scored 135 on one test battery and 123 on Raven’s Advanced Progressive Matrices.

What IQ do you need to join Mensa?

You need a score at or above the 98th percentile on an accepted test. That is about 130 on an SD 15 scale, but the exact number varies by test.

Conclusion

The highest IQ in the world is less a single number than a set of stories, each with its own level of proof. Marilyn vos Savant’s 228 and Kim Ung-yong’s 210 come from real childhood tests. Terence Tao’s 220 to 230 is a careful estimate. Many of the other famous figures, including William James Sidis’s 250 to 300 and YoungHoon Kim’s 276, are claims that do not hold up well.

The achievements are easier to measure than the scores: an Olympiad gold at 13, a Fields Medal, a Harvard degree at 16. For a closer look at high achievers at home, read our list of the Top 10 Highest IQ in India 2026.