IQ 100

About 68% of people score between 85 and 115, and 100 sits inside that range, right at the exact midpoint of 100. Around 50% of people score at or below 100 and 50% score higher. It sits exactly on the mean.

Average is not a polite word for mediocre. It is where the test is designed to place the typical adult, and it is the level that most schooling, jobs and everyday tasks are built around.

Most of the difference between people with average scores comes from other things: knowledge, experience, habits and how often they practise the kind of thinking a task needs.

In daily life a 100 means your reasoning on fast, unfamiliar puzzles matches the typical adult exactly. Half of people score higher and half lower, which makes it the reference point every other score is measured from.

Where a score like this shows is mainly in speed on unfamiliar, timed problems. Given time, familiar material and a clear goal, people across the average range reach the same answers.

School results in this range depend heavily on teaching, effort and interest. The same score turns up in students with top grades and in students who struggle.

Two people who both score 100 can have very different strengths underneath. These habits help whichever pattern you have:

• Lean on structure. Checklists, notes and routines free up working memory for the hard part of a problem.
• Learn in the format that suits you. Some people learn fastest by doing, others by reading or by talking it through.
• Go deep in one area. Expertise lets people reason quickly in their own field whatever their overall score.

If IQ follows the standard bell curve, 50% of people score 100 or higher. Here is what that share means across whole populations:

Near the middle of the curve, rarity barely changes from point to point. About 50% of people score 100 or higher, compared with 63% at 95 and 37% at 105.

What your 100 could really be. If you retook a well-made test, landing at 95 or at 105 would be unremarkable. That is the difference between beating 36.9% and 63.1% of people, and short online tests are noisier still.

Which scale was it on? At exactly 100 it makes no difference. Every standard IQ scale puts its average at 100, whatever standard deviation it uses.

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

No historical figure on this site has an estimate close to 100. Retrospective estimates cluster between about 115 and 250 because they are only made for people with exceptional achievements. That is a selection effect, not a sign that famous or successful people cannot score 100.

A few degree, university and job profiles on this site carry IQ benchmarks close to 100. Treat the education figures as rough estimates from admissions-test data rather than measured IQs.

IQ tests are normed so that the average adult scores 100, with a standard deviation of 15. By design, 100 is the mean, median and most common score of the model distribution.

The approach traces back to Lewis Terman's 1916 Stanford-Binet, although modern tests compare you with people your own age rather than using the old mental-age ratio.

Raw test performance rose across much of the twentieth century, often by around 3 points a decade (the Flynn effect). That is one reason tests are re-normed periodically, so that 100 keeps meaning average for the current population.

Nearby scores and the round-number landmarks, so you can see how quickly the percentile changes around 100. Every row links to that score's page.

People with an IQ of 100 typically score about 990 on the SAT and about 17 on the ACT composite. Scores vary a lot from person to person, so the range shows where about four in five land.