What Is the Average IQ Score?

On this page

1. What is the average IQ score?
2. What is a normal IQ score?
3. Why does the average stay at 100?
4. Is the average different for adults, teenagers and children?
5. Why do online IQ averages look higher than 100?
6. Is an average score good?
7. What is an above average IQ?
8. What is a below average IQ?
9. Why might your score move away from 100 on a retest?
10. How is the middle set on our own test?
11. How can you check your own score against the average?
12. FAQ

The average IQ is 100. Tests are built so that the middle person in the comparison group scores exactly 100. Most people land close to it: half of all people score from 90 to 109.

What is the average IQ score?

It is 100 on every modern IQ test. Test makers set it there on purpose. When a test is built, a large norming sample takes it first. That is the group whose results set the scale. The average score of that sample is then defined as 100.

So the average is not a finding that could turn out to be 97 or 104. It is a rule of the scale. In Wechsler’s method, anyone who scores at the mean of their age group gets exactly 100.

The spread around the average is set too. On most tests, one standard deviation is 15 points. A standard deviation (SD) is the typical distance from the average. Some tests use 16 instead, but the average is still 100.

What is a normal IQ score?

A normal IQ score is anything from 90 to 109, the band that both common label systems call Average. About 49.5% of people score in it. That is why a result in this band is the most typical result there is.

• 130 and above: Extremely High (WISC-V wording), Very Superior (traditional wording), 2.5% of people
• 120 to 129: Very High (WISC-V wording), Superior (traditional wording), 7.2% of people
• 110 to 119: High Average (WISC-V wording), High Average (traditional wording), 16.6% of people
• 90 to 109: Average (WISC-V wording), Average (traditional wording), 49.5% of people
• 80 to 89: Low Average (WISC-V wording), Low Average (traditional wording), 15.6% of people
• 70 to 79: Very Low (WISC-V wording), Borderline (traditional wording), 6.5% of people
• 69 and below: Extremely Low (WISC-V wording), Extremely Low (traditional wording), 2.1% of people

A second, wider definition is also common: 85 to 115. That is one standard deviation on either side of 100. The American Psychological Association describes it as a little over two thirds of people¹. Our own calculation gives 68.3%.

Both definitions are fair, as long as you say which one you mean. The narrow band matches the labels on test reports. The wide band matches the statistics of the bell curve.

Going further out, more than 95% of people score between 70 and 130. Scores outside that range are uncommon at both ends. The IQ scale shows every band with its share.

Why does the average stay at 100?

It stays at 100 because tests are re-normed: new norming samples reset the middle every so often. This matters because raw scores have not stood still.

Here is what happened, in order. First, researchers noticed that people were getting more raw questions right than earlier groups had, in many countries. This rise became known as the Flynn effect. It ran at roughly 9 IQ points per 30 years⁹. It was larger for fluid reasoning, such as puzzles, than for learned knowledge.

Next, test makers had to respond. If an old test had kept its old norms, the average person would have scored above 100. So each new edition got a fresh norming sample, and the middle went back to 100.

Later, some countries saw the rise slow down and even turn around. In Norwegian military testing data, the rise, its turning point and the later fall all appeared within families. The researchers read this as evidence of environmental causes, not of changes in who had children⁵.

The lesson for you is simple. A score belongs to one test and one set of norms. Comparing scores from tests normed at very different times can mislead.

Is the average different for adults, teenagers and children?

No. The middle is 100 at every age, because each person is compared with people of their own age. A 15-year-old is compared with 15-year-olds, and a 45-year-old with 45-year-olds.

This means a teenager with a score of 100 and an adult with a score of 100 are both exactly average for their age. It does not mean they solve the same questions. In childhood, older children generally solve more than younger ones, which is why each age has its own norms.

Tests for children and tests for adults are different tests, with their own norms. Our own test is not designed for children. The page on the score of 100 explains what it means at any age.

Why do online IQ averages look higher than 100?

Online averages often look higher than 100 for two reasons: who takes the tests, and how they are taken. Neither means people are smarter online.

The first reason is self-selection. People choose to take online tests, and those who choose are not a random slice of everyone. Research on web surveys shows that self-selection can make results unreliable for the whole population⁷.

The second reason is the setting. A review of 49 studies compared unsupervised online ability tests with supervised ones. Unsupervised scores were higher by about 0.2 of a standard deviation. That is about 3 IQ points⁶. The gap was smaller for tasks that are hard to look up.

So when a site says its visitors average 110 or more, be careful. That number describes the site’s visitors on that test, not people in general. Our methodology explains how we report our own numbers.

Is an average score good?

An average score is the most common result: it is what the largest group of people score. Average does not mean weak. It means typical, and the scale does not grade people in any case.

A score of 100 is at the 50th percentile. A score of 95 is at the 36.94th percentile, and 105 is at the 63.06th percentile. Small differences inside the average band say very little about a person.

Remember that any score has error. Even a full clinical test reports a range, not a single exact number. In one publisher’s sample report, a full-scale IQ of 111 has a 95% range of 106 to 116.

What is an above average IQ?

An above average IQ is a score of 110 or more, above the average band. Scores from 110 to 119 are called High Average in both common label systems. About 16.6% of people score in that band.

A score of 115 is one standard deviation above the average, at the 84.13th percentile. See what a 115 IQ means for its full profile.

Scores of 120 and up are clearly high, and 130 and up is the top band. The popular idea of a “genius” line is explained in what IQ is considered genius. Claims about the very top are covered in the highest IQ score.

What is a below average IQ?

A below average IQ is a score under 90, below the average band. Scores from 80 to 89 are called Low Average in both systems, and they are common. A score of 85 is one standard deviation below the average, at the 15.87th percentile.

See what an 85 IQ means for more. A single score is never a diagnosis, and online scores are only estimates.

Why might your score move away from 100 on a retest?

Your score can move on a retest because every test has measurement error, and because practice helps. Neither means your ability changed.

Measurement error is the normal wobble of any test. The standard error of measurement describes it: how much a person’s score would vary over many sittings. Clinical tests keep it small, but not at zero.

Practice also counts. A large review of retest studies found that scores rise when people take a test again. The gains stopped after the third attempt, and they depended on the type of test and the time between sittings⁸. So a second result a few points higher is normal, and it does not mean you got smarter.

How is the middle set on our own test?

Our own test puts its middle at 100 too, but its norms are still provisional. Until enough people have taken it, the scale comes from a statistical model, not from a norming sample of real people. We say so on every result.

Because of that, our results come with a wide range. When our test shows 100, the 90% range printed beside it is usually about 88 to 112. Our methodology explains how the range is made and when the norms will be updated.

How can you check your own score against the average?

To check your own score against the average, you need a score from a test with norms. Our free IQ test gives an estimate with a range in one sitting. The IQ calculator then turns any score into a percentile.

FAQ

What is the average IQ score for adults?

For adults it is 100, the same as for every other age group. Adults are compared with adults of their own age.

What is a normal IQ score?

A normal IQ score is 90 to 109, the average band. A wider definition, 85 to 115, covers about two in three people.

What is the average IQ for a teenager?

For a teenager it is 100. Teenagers are compared with others of the same age, so the middle is always 100.

What is the average IQ score in America?

On tests normed in the United States, the US average is 100 by definition. We do not publish rankings of countries, because we only publish data we can check.

What is the standard error of measurement on an IQ test?

The standard error of measurement (SEM) is how much a person’s score would vary if they took the test many times. A smaller SEM means a more precise score. In one clinical sample report the SEM is 3.00 points. Read are IQ tests accurate for more.

Does the average score change over time?

Raw scores change over time, but the IQ middle does not, because tests are re-normed. The rise in raw scores is called the Flynn effect.