What an IQ of 120 Means, and What It Does Not
On the scale most modern tests use, 120 sits around the 91st percentile. Change the scale and the same number moves. Add the measurement error every test carries and it stops being a point at all.
What you need to know
- On the scale most modern tests use (mean 100, standard deviation 15), an IQ of 120 is the 90.88th percentile, about the 91st: roughly 1 in 11 people score higher.
- On other scales the same 120 sits lower: the 89.44th percentile with a standard deviation of 16 and the 79.77th on the 24-point Cattell scale. The scale decides the percentile.
- Every score carries measurement error. A responsibly reported result is a range several points wide, not a point, and two scores inside that range are not meaningfully different.
- A percentile is a position in a reference sample, not a fixed rank among people. It moves when the reference sample changes or ages.
What an IQ of 120 means: it is about the 91st percentile on the scale most modern tests use (mean 100, standard deviation 15): 90.88% of people in the reference sample score lower, so roughly 1 in 11 scores higher. On a 16-point scale the same 120 is the 89.44th percentile, and on the 24-point Cattell scale only the 79.77th. Every single score also carries a margin of error of a few points.
What percentile is an IQ of 120?
On the standard scale, an IQ of 120 is the 90.88th percentile, so about 9 in 100 people score higher. People search for this as "what percentile is 120 IQ", "120 IQ percentile" or "IQ 120 percentile", and the answer is the same. The list shows the nearby scores, from 110 to 140.
- IQ 110: 74.75th percentile, about 1 in 4 score higher
- IQ 115: 84.13th percentile, about 1 in 6 score higher
- IQ 120: 90.88th percentile, about 1 in 11 score higher
- IQ 125: 95.22th percentile, about 1 in 21 score higher
- IQ 130: 97.72th percentile, about 1 in 44 score higher
- IQ 135: 99.02th percentile, about 1 in 100 score higher
- IQ 140: 99.62th percentile, about 1 in 260 score higher
These figures are our normal-curve arithmetic, and the method is short: subtract 100 and divide by 15 to get a z score (for 120, 20 / 15 = 1.33), then read the share of the curve below it. Our IQ percentile calculator does the same sum for any score, and the guide to how rare a high IQ score is explains the higher rows. A percentile is a position in a reference sample, so a real test's published table can differ by a point or so.
Is an IQ of 120 high?
Yes, it is clearly above average: higher than about 91 in 100 people on the standard scale. Whether it counts as high depends on the comparison and the scale, and our guide on whether a 120 IQ is high answers that question directly. For the next steps up, see the pages on an IQ of 125 and an IQ of 135, and the IQ classification ranges that different publishers use.
What is an IQ of 120 on a 16-point or 24-point scale?
On a scale with a standard deviation of 16, an IQ of 120 is the 89.44th percentile, and on the 24-point Cattell scale it is the 79.77th (our arithmetic). The scale decides the percentile.
- Mean 100, standard deviation 15 (the Wechsler scales and most contemporary tests): 120 is the 90.88th percentile
- Mean 100, standard deviation 16 (Stanford-Binet forms up to the fourth edition): the same 120 is the 89.44th percentile
- Mean 100, standard deviation 24 (the Cattell scale, used by some high-IQ societies): 120 is the 79.77th percentile, about 1 in 5 score higher
- Ratio IQ, the historical formula of mental age over chronological age: it has not been used in serious testing for generations, and childhood figures quoted in that form do not convert cleanly to a modern score
This is why a printed number without its scale is close to meaningless, and why comparing two people's scores from two different tests is a conversion problem, not a subtraction problem. Our guide to IQ standard deviation 15 vs 16 shows the conversion step by step.
A score is a position in a specific reference sample on a specific scale — not a quantity of anything you carry around.
How is an IQ score built?
Modern IQ scores are what psychometricians call deviation scores. They are not a ratio of anything. The test is given to a large reference sample chosen to represent a population, the raw results are arranged so the average is set to 100, and the spread is set so that one standard deviation equals a fixed number of points. Standard deviation is simply a measure of how spread out the scores are: on a scale where it is 15, roughly two in three people fall between 85 and 115, and roughly 19 in 20 fall between 70 and 130.
On that mean-100, standard-deviation-15 scale, a score of 120 is one and one-third standard deviations above the average, which places it at approximately the 91st percentile of the reference sample. Not the 95th, not "top 5%" — approximately the 91st, meaning roughly nine people in a hundred in that sample scored higher.
How accurate is a score of 120?
No test measures without error. Test manuals publish a figure called the standard error of measurement, which describes how much a person's observed score is expected to bounce around their true standing across repeated sittings. That is why a responsible report gives a confidence interval — a range within which the true score most likely lies — rather than a bare number.
The practical consequence is blunt: two scores a few points apart are usually indistinguishable. A 118 and a 122 are the same result. Someone whose score moved from 116 to 121 between two sittings has not improved; they have produced two estimates from the same band, which is what the band is for. Our guide to the IQ score margin of error shows how wide that range is.
What 120 does not tell you
- It does not describe any specific skill. It is a summary of performance across subtests that measure different things, and two people with the same total can have very different profiles.
- It does not predict an individual outcome. Test scores relate to group averages in education and work; the spread around those averages is wide enough that any single prediction is weak.
- It does not measure motivation, conscientiousness, judgement, creativity or knowledge of a field, all of which matter and none of which the score is built to capture.
- It does not stay fixed against an ageing reference sample. Norms expire, and a percentile computed against a sample from decades ago quietly drifts upward.
- It does not mean the same thing at 8 and at 48. Age-referenced scores compare you with your own age band, not with everyone.
Where would your own score land?
A number worth keeping comes with the three things above attached: the named scale it was measured on, the percentile against a stated reference sample, and the confidence range around it. If a result gives you a single figure and nothing else, the missing information is not a detail that was left out for simplicity — it is the part that would have let you check the claim.
Find your IQ score now! →None of this makes 120 uninteresting. On the standard modern scale it is a solidly above-average result, comfortably above the middle of the distribution and a long way from either extreme. It is simply a narrower statement than the internet treats it as: on this scale, against this sample, on this day, within this range. To see where your own score sits, take the IQ Metrics test, which reports a percentile with the score.
Common questions
Is an IQ of 120 high?
On the scale most modern tests use — mean 100, standard deviation 15 — it is clearly above average, at approximately the 91st percentile of the reference sample. It is not in the range usually described as very superior, and on a scale with a larger standard deviation, such as the Cattell scale used by some societies, the same printed number sits considerably lower.
Why do two tests give me different numbers?
Three reasons, all normal. They may use different scales. They may be normed on different reference samples. And every test carries measurement error, so repeated sittings scatter around your true standing. Differences of a few points are expected rather than surprising.
What percentile is 120?
It is the 90.88th percentile on a mean-100, standard-deviation-15 scale, about the 91st: roughly 9 people in 100 in the reference sample scored higher. On a standard-deviation-16 scale it is the 89.44th, and on the standard-deviation-24 Cattell scale the 79.77th. The percentile follows the scale, not the number.
How rare is an IQ of 120?
About 9 in 100 people score higher on the standard scale (mean 100, standard deviation 15), roughly 1 in 11. That is far more common than an IQ of 130, where about 1 in 44 score higher.
What is 120 IQ on a 16-point test?
On a scale with a standard deviation of 16, an IQ of 120 is the 89.44th percentile, so about 11 in 100 people score higher. On the 24-point Cattell scale it is the 79.77th percentile.
Sources for this story
- Technical and interpretive manuals for the Wechsler intelligence scales, covering scaling, norming and the standard error of measurement — Pearson
- Standards for Educational and Psychological Testing, on score reporting and confidence intervals — American Educational Research Association, American Psychological Association and National Council on Measurement in Education
- Hall v. Florida, 572 U.S. 701 (2014): opinion text read at law.cornell.edu/supremecourt/text/12-10882 on 11 November 2026 — Supreme Court of the United States
- Public guidance on psychological testing and assessment — American Psychological Association
- IQ Metrics normal-curve arithmetic, 11 November 2026 (Python statistics.NormalDist): percentiles for IQ 110 to 140 on standard deviation 15, and for 120 on 15, 16 and 24 — IQ Metrics
Corrections: spotted an error? Email corrections@iqmetrics.org and we will update this story and note the change here.
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