Top 2%
What IQ is the top 2 percent?
The top 2% is the line Mensa uses. Here is the score on three common scales, and what it takes to have one that counts.
Short answer
The top 2% of IQ scores starts at about 131 on the standard scale (mean 100, standard deviation 15); the exact cut is 130.8. That is the 98th percentile, about 1 in 50 people. On a scale with standard deviation 16 the cut is about 133, and on the SD 24 Cattell scale about 149.
Specimen · Top 2%
2%Top
- Cut at
- IQ 130.8
- Classification
- Very Superior
- z-score
- +2.05
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| Scale | IQ at the 98th percentile |
|---|---|
| Standard deviation 15 (Wechsler, SB5) | 130.8 |
| Standard deviation 16 (older Stanford-Binet) | 132.9 |
| Standard deviation 24 (Cattell Culture Fair III) | 149.3 |
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 2% of the curve above it, multiply by the scale's standard deviation and add 100. For the 98th percentile the z score is 2.054, so the cut is 130.8 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 132.9 and 149.3 there. The percentile to IQ converter does this for any percentile.
The top 2% and the Very Superior band
The WAIS-IV labels 130 and above Very Superior (Wikipedia: IQ classification), and 130 is the 97.7 percentile, so the band is roughly the top 2%. The top 2% line at 131 is labeled Very Superior.
Mensa accepts people at or above the 98th percentile on an approved, supervised test (Mensa International), about 131 on a scale with standard deviation 15. Mensa UK quotes 148 on Cattell III B and 132 on the Culture Fair test, both the 98th percentile on those scales (Mensa UK). The same percentile prints as very different numbers depending on the scale, which is the whole point of the table above.
A percentile is not a percentage of questions
The 98th percentile means scoring higher than 98% 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 131 |
|---|---|---|
| Top 1% | 134.9 | +4.1 |
| Top 3% | 128.2 | -2.6 |
See the score itself on IQ 131, 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
- About us. Mensa International. www.mensa.org/mensa/about-us
- IQ tests. British Mensa. www.mensa.org.uk/iq-tests