Who Is the Smartest Person Living? Why No One Holds the Title

Nobody can be named as the smartest person living, because no test can rank everyone alive. Standard IQ tests stop at about 160 on a scale with mean 100 and standard deviation 15, most people have never taken one, and Guinness World Records ended its "Highest IQ" category in 1990 because it judged IQ tests too unreliable to name a single record holder. So the "smartest person in the world" is a headline, not a measurement.

Below: why the title cannot be awarded, what happened to the Guinness record, how a ceiling of 160 hides the top of the scale, what to make of "smartest man in the universe" and "smartest man alive", and how to place your own score.

Who is the smartest person in the world?

No one can be named, because the title needs three things that do not exist. A ranking of everyone needs the same test taken by everyone, a scale that keeps working at the very top, and an independent body to check the result.

• No one has taken the same test: about 8.2 billion people are alive and only a small share have ever sat a full IQ test
• No scale reaches the top: standard tests report up to about 160, so people above that point get the same score
• No referee remains: Guinness World Records stopped naming a record holder in 1990
• No two tests agree: scores differ by test, by year of norms and by the standard deviation used (15, 16 or even 24)

Our guide to the highest IQ ever recorded traces each famous number back to its source. Most turn out to be childhood estimates, scores on unusual home-taken tests or figures on stretched scales. Our page on a 276 IQ claim shows how one such number was built and why independent experts did not accept it.

Why did Guinness stop naming the person with the highest IQ?

Guinness retired the "Highest IQ" category in 1990 because it concluded that IQ tests were too unreliable to designate a single record holder. That reason, and the dates, reach us through Wikipedia's article on Marilyn vos Savant, which cites Sam Knight in the Financial Times of 10 April 2009. We found no Guinness-owned page that states them, so treat them as reported, not confirmed by Guinness.

The start date is disputed. Wikipedia's text says the listing ran "from 1985 to 1989". Mental Floss writes that Guinness listed the holder "from 1986 to 1989". Both agree on the end: the last listing was in 1989 and the category was gone in 1990. We could not verify when the category was created. We also found no current Guinness record page for the highest IQ, though Guinness's own search could not be queried, so that is an absence of evidence, not proof.

Can any IQ test find the smartest person living?

No, because standard tests cannot tell apart people at the very top. The WAIS-IV, a Wechsler test, reports full-scale scores from 40 to 160 according to Wikipedia's description of the test; we could not read the publisher's own page. Our article on why scores stop near 160 explains the ceiling in detail.

Here is why that matters. An IQ of 160 on the standard scale is 4 standard deviations above the mean. On a normal curve that is about 1 person in 31,600. With 8.2 billion people alive, the curve predicts roughly 260,000 people at or above 160. That is our arithmetic, not a count of real people, and the normal curve is only a model at its far edge. Even if it held, the test would give all 260,000 the same top score.

A score also carries error. The same person tested twice usually scores a few points apart, so a gap of two or three points between two people means nothing. Use the IQ percentile calculator to see how fast the rarity grows near the top, and our page on the IQ score range for what each band is called.

Who is the smartest man in the universe, or the smartest man alive?

No one can be named for either phrase, because neither has a measurable meaning. "Smartest man in the universe" has no scale that covers anyone beyond Earth. "Smartest man alive" runs into the same problems as the smartest person in the world: no common test, no scale at the top and no referee.

What can be ranked is narrower. Prizes record achievement in one field, which is a different thing from an IQ score. Our look at the smartest mathematician alive shows what a count of top prizes can and cannot say about intelligence. For more, our celebrity IQ profiles label every figure as a test result, an estimate or a guess.

Why do "smartest person" lists disagree?

They disagree because each one uses a different yardstick. One list may use a childhood test, another a take-home puzzle with a few dozen test-takers, another a prize count. Each has its own scale, and a number from one cannot be placed next to a number from another.

• Ask which test it was, and who took it under what conditions
• Ask for the standard deviation: 15 is the Wechsler standard, but other scales use 16 or 24
• Ask how many people the norms were built on: a few dozen cannot support a rarity of one in millions
• Ask whether an independent body checked it

How can you find your own place on the scale?

You can place yourself, even if the top of the world cannot be ranked. A short, standard test gives a score and a percentile, which says how many people in the reference group score lower than you. That is a measurable claim, unlike a world title.

Start with the IQ test on our home page and read your result with the percentile calculator. For the data behind our scale and others, see our research.

Common questions