What does an IQ of 87 mean?
Below the average on the reference scale, at approximately percentile 19.31.
- IQ score
- 87
- Percentile
- 19.31
- At or above
- 80.69%
Normal reference · mean 100 · SD 15. These are calculated values, not observed starp population ranks.
Where 87 sits on the IQ scale
A score of 87 is 13 points below the mean. Dividing by the standard deviation gives (87 − 100) ÷ 15 = -0.87. The normal cumulative distribution converts that standardized position into percentile 19.31.
This lies in the lower half of the central 85–115 interval. A position below the mean is a comparison with the scale center, not a statement that every reasoning skill is below average.
How common is a score of 87?
Approximately 19.31% of this model lies at or below 87—about 1 in 5. This is a cumulative share, not the chance of scoring exactly 87. A continuous model does not assign a positive probability to one exact value.
Compared with IQ 85, the reference percentile is 3.44 percentage points higher. Equal IQ-point gaps do not create equal percentile gaps: the middle of the bell curve contains more area than its ends.
Compare nearby scores
Compare 82 and 87 or calculate 87 on another scale. A small difference between test results is not automatically a meaningful change.
How this relates to starp
starp's current scoring map does not produce exactly 87. Its neighboring results are 86 for 19 correct answers and 90 for 20 correct answers out of 30. This guide explains the conventional scale value 87; it does not invent an intermediate starp result.
See the scoring method and how raw scores differ from IQ estimates.
Questions about IQ 87
Is 87 a good IQ score?
87 is below the reference mean of 100. It should be interpreted in the context of the test, rather than as a verdict on a person's abilities or future.
What percentile is an IQ of 87?
On a normal scale with mean 100 and standard deviation 15, 87 corresponds to approximately percentile 19.31. Around 80.69% of that model lies at or above it. Use an assessment's own norms for an actual reported rank.
Does an IQ of 87 mean 87% correct?
No. IQ is a scaled score. Percentage correct depends on the questions and scoring rules; percentile describes a relative position. These three quantities are not interchangeable.
Method: NIST's normal-distribution formula. Percentiles here are calculated reference values, not observed starp population ranks. About starp scoring.