IQ 168

Taken literally, the bell curve puts 168 at 1 in 344,000: about 200 people in the UK and about 24,000 people worldwide. Treat that as an illustration of the model rather than a head count.

Major individually administered adult tests typically report full-scale scores up to about 160. A reported number above that usually comes from extended norms, a different scale or extrapolation.

Some tests publish extended norms above 160 for exceptional children. These rest on very small samples and on modelling, so they are best treated as rough rankings.

If someone tells you they have a 168, the first question is where the number came from. The usual answers:

• 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.
• Repetition without a source. Numbers attached to celebrities are often copied from site to site with no test report behind them.

Nobody in history has a measured IQ of 168. 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.

As far as anyone knows, Albert Einstein never took an IQ test. The 160 figure repeated online is an estimate. See the Einstein profile for what it rests on.

If IQ follows the standard bell curve, 0.00029% of people score 168 or higher. Here is what that share means across whole populations:

Going from 163 to 168 makes a score 4.6 times rarer, and going on to 173 multiplies the rarity by another 5.1. Near 168, each single point adds about 37% to the rarity.

What your 168 could really be. Even a good supervised test has a margin of error of roughly 5 points either side, and far more at this height. A true score from 163 to 173 would span rarities from 1 in 74,900 to 1 in 1.8 million.

Which scale was it on? Most modern tests use a standard deviation of 15, which is what this page assumes. If your 168 came from a test using an SD of 16, it is about 164 on the SD 15 scale. From an SD 24 scale, used by some Cattell-style reports, it is about 143.

Estimates this high are reserved for a small group of scientists, artists and thinkers. These sit near 168. None of these are test scores. They are estimates from biographical evidence, and each profile explains its basis.

How 168 stacks up against the scores just around it and the round numbers people usually ask about. Each score links to its own page.