What is the average IQ?

The short answer is 100. That is not a discovery, though. It is a definition. IQ tests are scaled so that the average person in the reference group scores exactly 100.

Why 100 is built in

An IQ score is a rank. Test makers give the test to a large sample chosen to represent the population, then convert raw scores so that:

• the average of that sample becomes 100,
• the standard deviation becomes 15,
• everyone else is placed on that scale by how far they sit from the average.

So asking “what is the average IQ?” is a bit like asking what the average percentile is: by construction it is the middle. The IQ scale explained covers the rest of the scale.

Average for your age

Adult IQ tests compare you with people of a similar age. A 70-year-old and a 25-year-old who both score 100 are each exactly average for their age group, even if their raw answers differ.

The Flynn effect

During much of the 20th century, raw scores on IQ tests rose steadily in many countries, by roughly three points per decade. This is known as the Flynn effect, after the researcher who documented it most widely. Better nutrition, schooling, health and more familiarity with abstract puzzles are all proposed causes.

Because of it, tests are renormed every so often. An old test scored against old norms makes people look better than they are, which is one reason outdated tests give inflated numbers.

Why online “averages” mislead

You will find plenty of online claims about average IQ by country, profession or star sign. Be cautious:

• Different tests, different samples. Numbers from different studies often cannot be compared directly.
• Self-selection. People who choose to take an online IQ test are not a random group. The average score on any particular website can be well above or below 100.
• Unclear scales. Some sources mix scales with different standard deviations.

That is also true of this site. Our results are scaled against the people who took this test, and the methodology page says so plainly.

What “average” means in everyday terms

• About half of people score between 90 and 110.
• About two thirds score between 85 and 115.
• A difference of a few points between two people is usually smaller than the margin of error of the tests themselves.

An average score is just that: the middle of a wide, ordinary range. It says nothing about creativity, character or the many skills that IQ tests do not cover (see what an IQ test measures).

Where do you land?

Take the free quick test to see your estimated range and where it sits on the bell curve. No email and no payment.