What Is a Good IQ Score? Ranges, Percentiles and What They Mean

By Eduard-Dragos Condria · Published October 10, 2026 · 8 min read

What counts as a good IQ score, how IQ ranges map to percentiles, and why a single number says less than most people think.

Ask ten people what a "good" IQ is and you will get ten answers, because the question mixes a statistical fact with a value judgement. The statistical part is easy. The value part depends on what you want the number for. This article covers both, and shows why most of what makes an IQ score meaningful sits outside the number itself.

How IQ scores are built

Modern IQ tests do not report the share of questions you got right. They compare your performance with a reference group of people your age and convert the result to a standard scale. On that scale the average is 100 and the standard deviation is 15. A standard deviation is a measure of spread: roughly two-thirds of people land within one standard deviation of the average, and about 95% within two.

That gives a fixed shape, the bell curve. About 68% of people score between 85 and 115. About 95% score between 70 and 130. Only about 2% score above 130 and about 2% below 70. These shares are a property of the scale, not a discovery about people: the scale is defined so that the average is 100 and the spread is 15, and tests are periodically re-standardised to keep it that way. The full table is on our IQ score chart.

IQ ranges and what they are called

Test publishers use descriptive labels for score bands. The labels differ slightly between tests (the Wechsler scales and the Stanford-Binet use different wording), but the bands are broadly these:

The shares come straight from the normal distribution; they will not match every real population exactly.

So what counts as "good"?

If "good" means "above average", anything over 100 qualifies, and most people who say they want a high IQ mean 120 or more. If "good" means "enough for what I want to do", the honest answer is that almost any score in the average range is compatible with almost any career or education path. IQ predicts some outcomes on average, such as years of schooling and job performance in complex roles, but the relationship is far from deterministic. Large studies typically find correlations in the range of roughly 0.2 to 0.6 between IQ and these outcomes, strongest for education and weaker for income. A correlation of 0.5 leaves most of the variation in outcomes to other things: motivation, conscientiousness, opportunity, health, luck and the quality of teaching and mentors.

It is also worth remembering what the number does not capture. IQ tests sample reasoning, working memory, processing speed and verbal or spatial knowledge. They do not measure creativity, practical judgement, persistence, social skill or wisdom, and these matter at least as much in most lives.

A score is a range, not a point

Every test has measurement error. The standard error of measurement for good professional tests is about 2 to 3 points, which gives a 95% confidence interval of roughly plus or minus 5 to 6 points. A score of 112 on one occasion is consistent with a "true" score anywhere from about 107 to 117. On a short unsupervised online test the error is larger. That is why we report an interval on our own IQ test and why we say the figure is an estimate, not a diagnosis. For more on this, read Are online IQ tests accurate?

Scores also move for reasons that have nothing to do with ability. Sleep loss, illness, distraction, anxiety and unfamiliarity with the puzzle format all lower results. Practice on similar tasks raises them: people who retake the same Wechsler test within a few months typically gain a few points.

What about very high scores?

Scores above about 145 are hard to measure at all. Few people score that high, so the test developers have little data in that region, and the tests have few items that separate a 145 from a 160. Claims of IQs of 180 or 200 on internet tests are not meaningful. The Wechsler scales, for instance, do not give composite scores much beyond 160 and their precision falls well before that.

Does IQ change over a lifetime?

Rank order in IQ is fairly stable from adolescence into adulthood: people tend to keep roughly the same position relative to their age group. But the scale is relative to age. Fluid reasoning (solving new problems) peaks in early adulthood and declines gradually, whereas vocabulary and general knowledge keep growing into later life. We explain the split in fluid vs crystallized intelligence. In childhood, scores are less stable, which is one reason a single childhood IQ score should not be treated as a fixed trait.

A sensible way to use an IQ result

• Treat it as one data point about a particular kind of reasoning on one day.
• Read the range, not the point estimate.
• Do not use an online score for school, employment or medical decisions. Those need an individually administered test given by a qualified psychologist.
• If a score worries you, or a child's learning is a concern, talk to a school psychologist or clinician rather than retesting online.

The most useful answer to "what is a good IQ score?" is that it depends on the question you are asking, and that curiosity about your own thinking is a better reason to take a test than a number to be proud of or worried about.

Sources

• Wechsler, D. (2008). Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV). Pearson. (score scale and descriptive classifications)
• Strenze, T. (2007). Intelligence and socioeconomic success: A meta-analytic review of longitudinal research. Intelligence, 35(5), 401–426.
• Neisser, U., et al. (1996). Intelligence: Knowns and unknowns. American Psychologist, 51(2), 77–101.
• Deary, I. J., Whiteman, M. C., Starr, J. M., Whalley, L. J., & Fox, H. C. (2004). The impact of childhood intelligence on later life: Following up the Scottish Mental Surveys of 1932 and 1947. Journal of Personality and Social Psychology, 86(1), 130–147.