The average IQ score is 100. IQ tests are deliberately designed and periodically recalibrated so that the score of a typical person, compared against others of the same age, lands at exactly 100. Scores spread out around this midpoint, and most people fall fairly close to it rather than at the extremes.
What is the average IQ?
The average IQ score is 100. This is true for every properly standardized IQ test, and it is true on purpose. When test-makers create or update an IQ test, they give it to a large, representative sample of people called a standardization sample. They then adjust the scoring so that the average performance of that group equals 100.
Because of this, an IQ score is not a count of how many questions you answered correctly. It is a comparison. A score of 100 means you performed about the same as the typical person in your age group. A score above 100 means you did better than the typical person, and a score below 100 means you did less well on that particular test, on that particular day.
IQ is a relative measure. Your number only has meaning in relation to everyone else who took a comparable test. There is no fixed "amount" of intelligence that equals 100 the way there is a fixed temperature that equals 0 degrees.
If you want to see roughly where you land relative to this midpoint, you can compare yourself against the average on our free IQ test. Just remember that any online result is an estimate, not a clinical diagnosis or a qualification for any society.
Why is 100 the average?
The number 100 is a convention, chosen because it is easy to work with. There is nothing magical about it. Test designers could have picked any number to represent the center, but 100 became the standard early in the history of intelligence testing and has stuck ever since.
The whole scoring system is built around two ideas:
- The mean (average) is set to 100. This is the midpoint that the typical test-taker is expected to reach.
- The standard deviation is set to 15. A standard deviation is a measure of how spread out scores are. On most modern tests it equals 15 points, which tells you how far a typical person drifts from the center.
Together these two settings create a predictable pattern. Because human performance on these tests tends to follow a bell-shaped distribution, fixing the average and the spread lets us describe the whole population with just those two numbers. Most people cluster near 100, and fewer and fewer people appear as you move toward the very high or very low ends.
One standard deviation above the mean is 100 + 15 = 115. Two standard deviations above is 100 + 30 = 130. The same works downward: 85 is one step below average, and 70 is two steps below. These round numbers are why you so often see 85, 115, and 130 used as reference marks.
What is the normal IQ range?
The "normal" or "average" range is usually described as 85 to 115, which covers one standard deviation on either side of 100. About 68% of people, roughly two in three, score within this band. Scoring here simply means your result is typical, which is by far the most common outcome.
The table below shows how scores spread out across the population. The percentages come directly from the bell-shaped distribution that test-makers design for, so they hold for any well-standardized test.
| IQ range | Description | Approximate share of people |
|---|---|---|
| 85–115 | Average range | About 68% |
| 70–130 | Within two standard deviations | About 95% |
| Above 130 | Well above average | About 2% |
| Below 70 | Well below average | About 2% |
A few things are worth keeping in mind when you read a range like this:
- Boundaries are soft. The difference between a 114 and a 116 is not meaningful in everyday terms. The labels are conveniences, not hard walls.
- Every score carries a margin of error. If you retook a test, your number would likely shift by a few points in either direction. No single result is the final word.
- "Average" is not a verdict. Most people are average by definition, and that is exactly what the system is designed to show.
For a closer look at how the bands are labeled and what they do and do not tell you, see our guides on IQ score ranges and what counts as a good IQ score.
Does average IQ vary by age or country?
This is where the design of IQ tests matters most. IQ scores are age-adjusted, which means your raw performance is always compared to others in your own age group. A ten-year-old and a forty-year-old who both score 100 are each average for their own age, even though they answered very different questions. Because of this adjustment, the average IQ stays at 100 across age groups by design. The score reflects how you compare to your peers, not a fixed quantity that rises or falls as you grow older.
You will sometimes see lists ranking the "average IQ" of different countries. Treat these with real caution. Such comparisons depend heavily on which test was used, how it was translated, who was sampled, access to schooling, and many other factors. They are easy to misread and easy to misuse, and a single national number hides enormous individual variation.
The cleaner way to think about it is this: within any given standardized testing group, the average is anchored to 100. Comparing averages across very different populations, languages, and education systems is far less straightforward than a tidy ranking makes it appear, and honest reporting acknowledges that uncertainty rather than hiding it.
Has average IQ changed over time?
Yes, in an interesting and somewhat counterintuitive way. Over the course of the 20th century, researchers noticed that people were performing better on the raw questions of intelligence tests from one generation to the next. This long-running rise in raw scores is known as the Flynn effect, named after the researcher who documented it extensively.
Here is the part that surprises people: even though raw performance climbed, the reported average IQ stayed at 100. That is because test-makers periodically renorm their tests. When a test is updated, it is given to a fresh standardization sample, and the scoring is reset so the new group's average is once again 100. Renorming keeps the scale stable so that a 100 today means the same thing in relative terms as a 100 from an earlier era.
Why raw scores rose is still debated. Commonly suggested contributors include:
- More years of formal schooling and greater familiarity with test-style questions.
- Improved nutrition and health in childhood.
- More complex, information-rich everyday environments that reward abstract reasoning.
The Flynn effect is about raw test performance drifting upward over decades, not about the average IQ number changing. Periodic renorming is exactly what holds the average at 100. There has also been discussion of the trend slowing or reversing in some places in recent years, but the core point stands: the scale is reset to keep 100 as the anchor.
If you are curious about the mechanics of how raw answers become an IQ number in the first place, our explainer on how IQ tests are scored walks through the process step by step.
Is 100 a good IQ?
An IQ of 100 is the exact average, which means it is a perfectly typical, normal result. Calling it "good" or "bad" misses the point, because the score is built to put most people right around this mark. A single number tells you very little about someone's real strengths, skills, or potential.
What percentage of people are average?
About 68% of people, roughly two in three, score within the average range of 85 to 115. If you widen the window to 70–130, you capture about 95% of everyone. In short, the large majority of people land fairly close to the center, and extreme scores at either end are genuinely rare.
What is the Flynn effect?
The Flynn effect is the observed rise in raw intelligence-test performance across generations during the 20th century. Despite this rise, the reported average IQ has remained 100 because tests are periodically renormed against a fresh sample. So the trend describes improving raw scores, not a moving average.