IQ 177

Taken literally, the bell curve puts 177 at 1 in 7 million: about 10 people in the UK and about 1,200 people worldwide. Treat that as an illustration of the model rather than a head count.

No test has enough people in its norm sample to check its accuracy at 177. In a 2,200-person sample the bell curve expects effectively nobody at 177 or higher.

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.

Most very high numbers you see online come from one of a few sources, and knowing which one produced a 177 tells you how much weight to put on it.

• Ratio IQ. Early childhood tests divided mental age by real age. A 6-year-old solving puzzles like a typical 10.6-year-old got a ratio IQ of 177. Modern deviation IQs do not work this way.
• Different scales. Some tests use a standard deviation of 24, so a 177 there is about 148 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.

Isaac Newton and Leonardo da Vinci are usually given estimates of 160 or more, and they are among 42 such profiles here. Only 4 go as high as 177. All are judgements from biographies, not test results.

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 177 or higher is a 0.000014% share of everyone. Scaled up to whole populations, that works out as:

Going from 172 to 177 makes a score 5.6 times rarer, and going on to 182 multiplies the rarity by another 6.2. Near 177, each single point adds about 43% to the rarity.

What your 177 could really be. At this height the margin of error is wide. Just 5 points either way, 172 or 182, changes the model rarity from 1 in 1.3 million to 1 in 44 million, which shows how fragile such numbers are.

Which scale was it on? Score reports do not always say. On the common SD 15 scale your 177 stands as it is. If the report used SD 16 it equals about 172, and if it used SD 24 about 148. The percentile follows the converted number.

Nobody famous has a verified IQ in most cases, and retrospective estimates are only made for a narrow group.

The estimates on our historical profiles run from 115 to 250, so none lands close to 177. Historians only estimate IQs for people who did something extraordinary, which skews the list. It says nothing about what famous people could actually score.

How 177 stacks up against the scores just around it and the round numbers people usually ask about. Each score links to its own page.