Guide
What is the average IQ?
The average IQ is 100. That is not a measurement that happens to land on a round number. It is how the scale is defined. The more interesting questions are what counts as "average", what range is normal, and why the average has to be reset over time.
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Why the average is exactly 100
Modern IQ tests report a deviation IQ. A publisher gives the test to a large sample of people at each age, then standardizes the results so that the mean for each age group is 100 and the standard deviation is 15 (Wikipedia: Intelligence quotient). Your score is a comparison with that sample.
So “the average IQ is 100” is true by construction, for every age group, on every properly normed test. It is the same kind of statement as “the median height is the height half of people are above”. If you score 100, you did exactly as well as the typical person your age in the test's reference sample.
What counts as average?
There are two conventions, and both are in common use.
The WAIS-IV label: 90 to 109
The Wechsler Adult Intelligence Scale (fourth edition) labels scores from 90 to 109 as “Average”(Wikipedia: IQ classification). From the normal curve, about 49.5% of people score in that band, making it the largest of the seven labels. Just above it is High Average (110 to 119) and just below is Low Average (80 to 89).
One standard deviation: 85 to 115
Statisticians often describe the typical range as everything within one standard deviation of the mean. On the IQ scale that is 85 to 115, and it holds about 68% of people (the 68-95-99.7 rule). By this definition, 112 is within the typical range even though the WAIS-IV labels it High Average.
Neither convention is wrong. They answer slightly different questions. The labels describe bands on one specific test; the standard deviation describes the spread of the whole curve.
Try one · Logical Reasoning
Which tile completes the second pair?
Tap the option you think is right, or show the answer.
Show the answer
The missing panel shows a small solid circle, with small solid shapes: a triangle at the bottom (option 6).
How to solve it
- Compare the first two panels and name exactly what changed.
- The main shape and the small shapes swap forms: the main shape takes the form of the small ones, and the small ones take the form of the main shape.
- Nothing else changes.
- Apply the same change to the third panel: a small solid triangle pointing up, with small solid shapes: a circle at the bottom.
- So the missing panel shows a small solid circle, with small solid shapes: a triangle at the bottom.
That was 1 puzzle. The full test has 25.
Average is relative to your age
Because scores are standardized within each age group, a 25-year-old and a 70-year-old who both score 100 are each exactly average for their age. They may not have answered the same number of questions correctly. This is why your IQ does not fall just because you get older, even though some abilities, like raw processing speed, change with age. Our guide to IQ and age explains what the research found.
Why the average has to be reset
Through much of the 20th century, average performance on IQ tests rose. A 2015 meta-analysis of 271 samples, covering about 4 million people in 31 countries from 1909 to 2013, estimated the gain at about 2.8 points per decade, with gains slowing in recent decades (Pietschnig & Voracek, 2015). In Norwegian conscript data, the trend has reversed for people born after about 1975 (Bratsberg & Rogeberg, 2018). This is the Flynn effect.
Think about what that does to a test. If the reference sample was tested decades ago and average performance has risen since, today's typical person beats the old average, and the test would report scores above 100 for people who are in fact average now. To keep 100 meaning average, publishers standardize new editions against new samples. The Wechsler adult scale, for example, has gone through several editions, with WAIS-IV published in 2008 and WAIS-5 in 2024 (Wikipedia: WAIS).
Average IQ by country, job or group
You will find many lists online claiming the average IQ of a country, a profession or a famous person. IQ Octopus does not publish figures like these. They depend on which tests were used, how samples were chosen, how old the data is and how results were converted between scales, and we have not found sources we are willing to stand behind. Where a number cannot be traced, we leave it out.
What we can say with confidence is what follows from the scale itself: 100 is the mean, 15 points is one standard deviation, and percentiles and rarities follow from the normal curve. The IQ score chart lists them for every score from 70 to 160.
Being average is not a verdict
Half of all people score at or below 100, by definition. An average score means your reasoning on this kind of task is typical for your age. It says nothing about your knowledge, skills, character or what you can achieve with effort and good habits. Most of the things people care about are not measured by an IQ test at all, as our guide to what an IQ test measures explains.
If you want to see where you fall, the IQ Octopus test takes about 12 minutes, and your result shows your estimated IQ on the curve with a confidence range. For the full picture of the curve itself, read the IQ bell curve, explained.
Sources
- Intelligence quotient. Wikipedia. en.wikipedia.org/wiki/Intelligence_quotient
- IQ classification. Wikipedia. en.wikipedia.org/wiki/IQ_classification
- 68-95-99.7 rule. Wikipedia. en.wikipedia.org/wiki/68%E2%80%9395%E2%80%9399.7_rule
- Pietschnig, J., & Voracek, M. (2015). One century of global IQ gains. Perspectives on Psychological Science, 10(3), 282-306. doi.org/10.1177/1745691615577701
- Bratsberg, B., & Rogeberg, O. (2018). Proceedings of the National Academy of Sciences, 115(26), 6674-6678. doi.org/10.1073/pnas.1718793115
- Wechsler Adult Intelligence Scale. Wikipedia. en.wikipedia.org/wiki/Wechsler_Adult_Intelligence_Scale