IQ 171

Taken literally, the bell curve puts 171 at 1 in 904,000: about 75 people in the UK and about 9,000 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.

Real populations may not follow the bell curve perfectly in the far tails, so rarity figures this extreme are illustrations, not head counts.

If someone tells you they have a 171, the first question is where the number came from. The usual answers:

• Different scales. Some tests use a standard deviation of 24, so a 171 there is about 144 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 171. 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.

Scoring 171 or higher is a 0.00011% share of everyone. Scaled up to whole populations, that works out as:

An IQ of 171 or higher is 4.9 times rarer than 166 or higher, and 176 or higher is 5.5 times rarer again. At this point on the curve, each extra point makes a score about 39% rarer.

What your 171 could really be. No test is precise this far out. Even a 5-point error band, from 166 to 176, spans a rarity gap of about 27 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 171 stands as it is. If the report used SD 16 it equals about 167, and if it used SD 24 about 144. The percentile follows the converted number.

Estimates this high are reserved for a small group of scientists, artists and thinkers. These sit near 171. Every figure below is a retrospective estimate, not a measured score. Open a profile to see the evidence and how confident anyone can be.

The scores one and five points either side of 171, plus the round numbers from 100 to 150, side by side. Tap any score for its full page.