Home / Articles

What is the average IQ?

By Free IQ Test Lab Team · Published 14 October 2026 · 7 min read

The average IQ is 100, not measured, but set. IQ tests are deliberately built so the average comes out at 100, which makes the number itself the least interesting part of the story. The interesting part is everything people try to read into it: averages by age, by country, whether the average is rising or falling. Most of those questions turn out to have the same answer, and it starts with how the scale is constructed.

Why the average IQ is always 100

An IQ score is not a count of correct answers. When a professional test is published, it is first given to a large sample of people chosen to reflect the population — often a few thousand. Their results become the reference point, the norms. Your score then says how you did compared with that group, not how many questions you got right in absolute terms.

The scale is anchored so the middle of the group sits at 100, with one standard deviation — a measure of how spread out scores are — set at 15 points. Score 100 and you match the typical person in the reference group. Score 115 and you beat about 84 out of 100 of them. Score 85 and you beat about 16.

There is a maintenance step most people never hear about. If the general population starts answering more questions correctly over the years, the old norms would push the average above 100 — so every so often, publishers test a fresh reference group and reset the scale. The average stays 100 because someone keeps putting it there.

What is the normal IQ range?

Scores bunch up in the middle and thin out toward the edges. On the standard scale (average 100, standard deviation 15), the population splits like this:

IQ range	Share of people	Usually described as
Below 70	2.3%	Very low
70 to 79	6.9%	Low
80 to 89	16.1%	Below average
90 to 109	49.5%	Average
110 to 119	16.1%	Above average
120 to 129	6.9%	High
130 and above	2.3%	Very high

Two bands get called "normal." The narrow one, 90 to 109, holds about half of everyone. The wider one, 85 to 115 — one standard deviation either side of 100 — holds about 68%, roughly two in three people. Land anywhere in there and your score is typical. For the full breakdown of every band, see our IQ score chart.

Is the average IQ different for children, teens, or adults?

No. It is 100 at every age, and the reason is the same trick as before: tests compare you only with people your own age. A 10-year-old is measured against other 10-year-olds; a 60-year-old against other 60-year-olds. The tests even have different names on each side of the divide — the Wechsler Intelligence Scale for Children (WISC) up to about 16, the Wechsler Adult Intelligence Scale (WAIS) after.

That means an IQ of 100 does not represent the same raw ability at 8 and at 40. It means "middle of your age group" in both cases. What genuinely changes with age is the kind of reasoning people are best at: fast, unfamiliar problem-solving tends to peak in early adulthood, while vocabulary and general knowledge keep growing well into middle age. A well-built test separates those strands instead of blending them.

One caution for parents: a score taken at a young age can shift a lot by adulthood. Treat a single childhood result as a snapshot, not a forecast.

The average IQ in the US — and why country rankings deserve skepticism

The Wechsler tests and the Stanford-Binet are normed on samples built to mirror the US population, so the average American scores 100 on them — again, by construction. Other countries run their own editions with their own norms (UK, Australian, and others), and on each of those the national average is also set to 100. When you see a claim like "the average IQ in America is 98," it almost always comes from a different, shakier kind of comparison. Which brings us to the maps.

You have seen them: countries colored green at 108, red at 70, ranked like football teams. They are shared a lot and trusted more than they should be. The figures are stitched together from different tests given in different decades and converted onto one scale. For some countries the entire estimate rests on a few hundred people — sometimes a single school or town. People with years of timed, written schooling do better on timed, written tests, which measure education and familiarity as much as reasoning. And some of the numbers are decades old, from periods when scores were moving anyway (see below).

The best-known national datasets have taken heavy criticism from researchers on exactly these grounds. We do not publish a country table, and we would not trust one we found. If you are curious about a specific country, look for a recent, nationally representative study — then check which test was used and how the sample was chosen before believing the number.

The same logic kills the idea of a single "average human IQ" or "world average." Every modern test sets its own reference group to 100, so there is no global norm to measure against.

Is the average going up or down?

Through most of the 20th century, raw scores rose in many countries — around 3 points per decade, the figure usually quoted. The rise was far too fast to be genetic, which points at nutrition, schooling, and growing up around abstract problems. It is called the Flynn effect after James Flynn, who documented it.

Since the 1990s, the rise has stalled or reversed in some countries. A large study of Norwegian conscription records, covering men born between 1962 and 1991, found scores climbing then falling — and found the same pattern between brothers in the same family, which rules out most of the easy explanations. The authors concluded both the rise and the fall were environmental, not genetic (Bratsberg and Rogeberg, 2018).

None of this moves the published average, of course. Tests get re-normed, and the scale goes back to 100.

Population averages are one thing; your own score is another. If you are wondering whether an individual can lift theirs, we look at the evidence in our guide to whether you can increase your IQ.

What an average score means in everyday life

Less than the number's precision suggests. IQ tests measure a slice of reasoning — spotting patterns, working with numbers, following logic, and in full clinical tests, memory and speed. They do not measure creativity, practical skill, depth of knowledge, or how well you work with other people. Plenty of people with average scores do demanding, skilled work; plenty of high scorers struggle with things no IQ test touches.

An average score means your reasoning, on that test, on that day, was typical for your age group. That is the whole of it.

A rough idea of your own score

A formal assessment is a one-to-one session with a psychologist that takes an hour or more. For a rough estimate, our free IQ test comes in two lengths — a Quick test of 15 puzzles in 10 minutes, or a Full test of 40 puzzles in 30 minutes — covering five kinds of reasoning: patterns, numbers, logic, shapes, and analogies. Every attempt generates a new set of puzzles, so retaking it never shows you the same questions twice.

You get your estimated IQ with a likely range (12 points either side on the Quick test, 8 on the Full), your place among 100 people, a breakdown across the five areas, an explanation for every answer, and a free certificate with your name. No sign-up, nothing to pay. Our scoring method shows exactly how the estimate is worked out — including its limits.

Want a warm-up first? Daily Pattern gives you three fresh puzzles a day, each explained after you answer.