Yes. It is a very high score. On the standard IQ scale, 155 is above the 99th percentile, about 1 in 8,139 at or above.
An IQ of 155 sits in the very high range, higher than about 99.99% of people on a mean-100, SD-15 scale. This is a theoretical model comparison, not an observed population ranking. Here is what that means, and what it does not.
Reference score
155
Percentile
99.99%
At or above
1 in 8,139
Reference scale
100 mean / 15 SD
This is an educational guide to 155 on a reference scale. IQInsight’s estimate range ends at 145 and cannot produce 155.
Prepared by IQInsight · Calculation guide · Updated
155 is more than three and a half standard deviations above 100.
On the mean-100, SD-15 model, 155 has a z-score of about 3.67. Only about 0.012% of values fall at or above it, roughly one in 8,139. IQInsight cannot produce this score; its estimates end at 145.
Estimates this far into the tail are rarely precise. Professionally developed tests need large, well-designed norm samples to distinguish 150 from 155, and many do not report scores this high at all. A precise model probability does not make a measurement accurate.
How test manuals label 155.
Professional tests describe score ranges with standard labels. On the WAIS-IV, 155 falls in the very superior range; the newer WISC-V calls the same range extremely high. The labels describe ranges on those specific tests and change at fixed boundaries, so a score a point or two from an edge is not meaningfully different from one just across it.
Descriptive classifications used by the WAIS-IV and WISC-V
Score range
WAIS-IV label
WISC-V label
130 and above (155)
Very superior
Extremely high
120–129
Superior
Very high
110–119
High average
High average
90–109
Average
Average
80–89
Low average
Low average
70–79
Borderline
Very low
69 and below
Extremely low
Extremely low
High-IQ societies such as Mensa admit people who score at or above the 98th percentile on an approved, supervised test, roughly 130 on an SD-15 scale. Online estimates, including IQInsight’s, do not count toward membership.
How precise is one result?
Every test score contains some measurement error. Professionally normed tests report a confidence interval, a band of several points around the score, and two results a few points apart often overlap. IQInsight has not been calibrated against a representative population, so it cannot provide a reliable interval for its estimates.
How the percentile is calculated.
The reference uses a mean of 100 and a standard deviation of 15. First convert the score to a z-score, then find the area below it on the standard normal curve.
Theoretical normal distribution. Mean 100, standard deviation 15. This does not measure your IQ or compare you with IQInsight users.
Put the number in perspective.
In a normal distribution with mean 100 and standard deviation 15, about 0.01% of scores fall at or above 155. That is approximately one in 8,139. The figure describes the reference model; it is not a count of people we have tested.
The quality of the test matters.
A number alone does not show how accurately it was measured. An established, professionally administered test has supporting evidence and defined interpretation rules. An online exercise without representative norms cannot establish the same conclusions.
Nearby scores on the same scale.
Theoretical percentiles, mean 100 and standard deviation 15
Treat a reported 155 as a claim to verify: which test, which scale and which norms. The rarity figure only applies if the measurement behind it supports this part of the scale.
A score alone cannot tell you how a person thinks through a problem. This published sample illustrates a reasoning method; it is not calibrated to a 155 IQ level and does not predict a score.
At step 0, a marked arrow points up. Every step rotates the whole figure 90° clockwise. After every even-numbered step, reflect it top-to-bottom across a fixed horizontal line. Which complete figure appears at step 5?
A. Right, with the mark below the arrow
B. Right, with the mark above the arrow
C. Left, with the mark above the arrow
D. Up, with the mark on the right
Reveal the answer and reasoning
Answer: Right, with the mark below the arrow. The directions after full steps are right, up, right, up, right. At step 4 the whole figure is back at its starting position. The fifth clockwise turn points right and puts the original right-side mark below the arrow.
Check an alternative: Right, with the mark above the arrow. The direction matches step 3, but the mark has the wrong reflected position for step 5.
Try this approach. Track both the arrow tip and the asymmetric mark; apply rotation before reflection on even steps.
This is one of our public sample questions. Seeing the solution may make a future attempt more familiar. Explore the sample report to see how answers are explained.
A few things you might be wondering.
Clear answers, before you begin.
Can an online test measure an IQ of 155?+
Not reliably. Short online tests rarely have norms that support scores this high, and IQInsight’s estimate stops at 145. Confirming a score in this range requires a professionally administered test that reports its range and precision.
What percentile is an IQ of 155?+
On a scale with mean 100 and standard deviation 15, 155 is above the 99th percentile: about 0.01% of values are at or above it. Tests with a different standard deviation give a different percentile for the same number.
Is 155 a good IQ score?+
On a theoretical scale with mean 100 and standard deviation 15, 155 is in the very high range, higher than about 99.99% of people on a mean-100, SD-15 scale. This is a theoretical model comparison, not an observed population ranking. Whether a particular test result supports that interpretation depends on the quality and standardization of that test.
How rare is an IQ of 155?+
Under that normal-distribution model, about 0.01% of values are at or above 155, approximately 1 in 8,139. This is a mathematical reference, not observed IQInsight user data.
Does this number describe all of my abilities?+
No. IQ scores do not describe every skill, interest, quality or circumstance. A score on an unstandardized online exercise is especially limited and should not be treated as a diagnosis or a prediction of personal success.
Can I compare scores from different tests?+
Only with care. Tests can differ in norms, scales, questions, administration and reliability. Similar-looking numbers are not necessarily equivalent measurements.
Can I get my result without paying?+
Yes. IQInsight provides your estimated score, theoretical percentile and four-area breakdown for free. The optional report explains the answers in more detail.
