IQ 189

189 is 5.93 standard deviations above the mean. On a bell curve that works out to about 1 in 670 million people, which would mean fewer than one (0.10 expected) in the UK and about 12 worldwide. The bell curve is a model, though, and at this height it is doing most of the work.

No test has enough people in its norm sample to check its accuracy at 189. In a 2,200-person sample the bell curve expects effectively nobody at 189 or higher.

None of this means nobody is this able. It means a single number is not a reliable way to describe them.

If someone tells you they have a 189, the first question is where the number came from. The usual answers:

• Different scales. Some tests use a standard deviation of 24, so a 189 there is about 156 on the usual SD 15 scale.
• Historiometric estimates. Researchers such as Catharine Cox (1926) estimated IQs for famous people from biographies. Some of her adjusted estimates went above 200. They are educated guesses, not test results.
• Unnormed online quizzes. A test with no norm data can print any number. Very high outputs usually say more about the scoring than the person.

Nobody in history has a measured IQ of 189. The highest estimates on this site, for figures such as Isaac Newton and Leonardo da Vinci, come from reading their work and lives, not from tests. 42 profiles here are estimated at 160 or more.

Two people with identical estimates can have very different evidence behind them. Each profile explains what its estimate is based on and how confident anyone can be.

If IQ follows the standard bell curve, 0.00000015% of people score 189 or higher. Here is what that share means across whole populations:

Compare the neighbours: 184 or higher is about 1 in 93 million, 189 or higher is 1 in 670 million, and 194 or higher is 1 in 5.4 billion. Each point up here adds roughly 50% to the rarity.

What your 189 could really be. No test is precise this far out. Even a 5-point error band, from 184 to 194, spans a rarity gap of about 58 times, so the exact number matters much less than "very far above average".

Which scale was it on? Score reports do not always say. On the common SD 15 scale your 189 stands as it is. If the report used SD 16 it equals about 183, and if it used SD 24 about 156. The percentile follows the converted number.

Estimates this high are reserved for a small group of scientists, artists and thinkers. These sit near 189. Every figure below is a retrospective estimate, not a measured score. Open a profile to see the evidence and how confident anyone can be.

How 189 stacks up against the scores just around it and the round numbers people usually ask about. Each score links to its own page.