Top 15%
What IQ is the top 15 percent?
The 85th percentile on the bell curve, on three common scales, with what a score at that line means.
Short answer
The top 15% of IQ scores starts at about 116 on the standard scale (mean 100, standard deviation 15); the exact cut is 115.5. That is the 85th percentile, about 1 in 7 people. On a scale with standard deviation 16 the cut is about 117, and on the SD 24 Cattell scale about 125.
Specimen · Top 15%
15%Top
- Cut at
- IQ 115.5
- Classification
- High Average
- z-score
- +1.04
Want your own number? The test is 25 visual puzzles, about 12 minutes, no sign-up.
| Scale | IQ at the 85th percentile |
|---|---|
| Standard deviation 15 (Wechsler, SB5) | 115.5 |
| Standard deviation 16 (older Stanford-Binet) | 116.6 |
| Standard deviation 24 (Cattell Culture Fair III) | 124.9 |
How the cut is calculated
IQ scores are standardized to a normal curve with mean 100 (Wikipedia: Intelligence quotient). To find the score at a percentile, take the z score that leaves 15% of the curve above it, multiply by the scale's standard deviation and add 100. For the 85th percentile the z score is 1.036, so the cut is 115.5 on SD 15. Older Stanford-Binet forms used SD 16 and the Cattell Culture Fair III scale uses SD 24 (Wikipedia: IQ classification), which is why the same percentile reads as 116.6 and 124.9 there. The percentile to IQ converter does this for any percentile.
What a score at the top 15% line means
A score of 116 is labeled High Average on the WAIS-IV scale (Wikipedia: IQ classification). It is outside the 85 to 115 range where about 68% of people score (the 68-95-99.7 rule), so the top 15% is clearly above the typical range.
In a group of 30 people the same age, about 5 would be expected to score at or above 116. Percentiles near the middle of the curve are close together in points: a few IQ points can move you several percentiles, while out in the tails the same few points barely move the percentile at all.
A percentile is not a percentage of questions
The 85th percentile means scoring higher than 85% of people the same age, not answering that share of questions correctly. See whether an IQ score is a percentage for the difference.
Neighboring percentiles
| Percentile | IQ (SD 15) | Gap from 116 |
|---|---|---|
| Top 10% | 119.2 | +3.7 |
| Top 20% | 112.6 | -2.9 |
See the score itself on IQ 116, every cut on the IQ by percentile page, or any score on the IQ score chart.
Sources
- Intelligence quotient. Wikipedia. en.wikipedia.org/wiki/Intelligence_quotient
- IQ classification. Wikipedia. en.wikipedia.org/wiki/IQ_classification
- 68-95-99.7 rule. Wikipedia. en.wikipedia.org/wiki/68%E2%80%9395%E2%80%9399.7_rule