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What Percentage Has an IQ of 120? Top 9%, About 1 in 11

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In brief: On a normal distribution with a mean of 100 and an SD of 15, an IQ of 120 is roughly the top 9.1%, about 1 in 11 people, and a deviation score of 63.3. It is rarer than IQ 115 but far more common than IQ 130: a clearly above-average level.

An IQ of 120 is a frequently searched score — clearly above average, but short of the common gifted benchmark of 130. Here is how rare it actually is, along with the distribution logic behind the number.

An IQ of 120 is in the top 9% or so

On a normal distribution with a mean of 100 and a standard deviation of 15, an IQ of 120 sits about +1.33 standard deviations above the mean. That corresponds to roughly the top 9%, or about 1 in 11 people. In a school class of around 35, that is roughly the top 3 students. You can see the full shape of the distribution in the IQ distribution data.

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Where IQ 120+ sits on the distribution (mean 100, SD 15): roughly the top 9.12%.

Compared with IQ 115 and IQ 130

One step down, IQ 115 (+1 SD) is about the top 16%, roughly 1 in 6. One step up, IQ 130 (+2 SD) narrows sharply to the top 2.3%, about 1 in 44. IQ 120 sits right between the two, and converts to a deviation score of about 63. The conversion is explained in how to convert between IQ and deviation scores.

What kind of level is IQ 120?

Statistically, it is often described as a band commonly seen among university graduates and in intellectually demanding professions. But the link between IQ and academic or career outcomes is only a moderate correlation, and outcomes vary widely even within the same score band — a point we cover honestly in the relationship between IQ and income.

The number is only a relative position

An IQ of 120 indicates your relative position within your age group; it is not an absolute quantity of ability or a guarantee about the future. Scores can also shift by several points depending on the test and your condition on the day. You can see where each score falls in the IQ reference table.

Find out where you stand

If you want to know which band you fall into, the free IQ test gives you a balanced estimate of your IQ, deviation score, and top percentile. Start by checking where you stand today.

Frequently asked questions

What percentile is an IQ of 120?
On a normal distribution with a mean of 100 and an SD of 15, roughly the top 9.1%.
How rare is an IQ of 120?
Under the same model, about 1 in 11 people. In a class of 35, that is around 3 students in theory.
What deviation score is an IQ of 120?
Converted to a deviation score with a mean of 50 and an SD of 10, about 63.3.

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Editorial note & disclaimer

BrainRank Editorial Team

This article was written and edited by the BrainRank Editorial Team with reference to academic literature on psychometrics, including CHC theory and Item Response Theory (IRT). Statistics and percentages are calculated from a normal distribution model with a mean of 100 and a standard deviation of 15.

The tests on this site provide estimates for entertainment and self-understanding purposes only. They are not medical or clinical assessments, nor official psychological (intelligence) tests.

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