What does an IQ of 109 mean?
Above the average on the reference scale, at approximately percentile 72.57.
- IQ score
- 109
- Percentile
- 72.57
- At or above
- 27.43%
Normal reference · mean 100 · SD 15. These are calculated values, not observed starp population ranks.
Where 109 sits on the IQ scale
A score of 109 is 9 points above the mean. Dividing by the standard deviation gives (109 − 100) ÷ 15 = 0.6. The normal cumulative distribution converts that standardized position into percentile 72.57.
This lies in the upper half of the central 85–115 interval. It is above the scale mean, but the total alone does not identify a particular strength in memory, numbers or spatial reasoning.
How common is a score of 109?
Approximately 27.43% of this model lies at or above 109—about 1 in 4. This is a cumulative share, not the chance of scoring exactly 109. A continuous model does not assign a positive probability to one exact value.
Compared with IQ 100, the reference percentile is 22.57 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 104 and 109 or calculate 109 on another scale. A small difference between test results is not automatically a meaningful change.
How this relates to starp
starp's current 30-question scoring map produces 109 from 24 correct answers (80% correct). That accuracy percentage is different from the normal-model percentile above. The scoring map was calibrated with 12,700 simulated assessments; it is not population norming.
See the scoring method and how raw scores differ from IQ estimates.
Questions about IQ 109
Is 109 a good IQ score?
109 is above the reference mean of 100. It is a higher score on that scale, but a number alone cannot establish a specific skill profile or predict success.
What percentile is an IQ of 109?
On a normal scale with mean 100 and standard deviation 15, 109 corresponds to approximately percentile 72.57. Around 27.43% of that model lies at or above it. Use an assessment's own norms for an actual reported rank.
Does an IQ of 109 mean 109% 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.