IQ 128
Is 128 a good IQ? What it means
128 is near the top of the Superior band, 1 point below the Very Superior line at 130. Here is what the score means, how rare it is, and how close it is to the next label.
Short answer
An IQ of 128 is well above average. It is higher than about 96.9% of people, which puts it at the 96.9 percentile. About 1 in 32 people score 128 or higher, and the WAIS-IV labels it Superior (120 to 129). It is 1.87 standard deviations above the mean of 100.
Specimen · IQ 128
128IQ
- Classification
- Superior
- Percentile
- 96.9
- Rarity
- 1 in 32
- z-score
- +1.87
Curious where you would land? IQ Octopus estimates your IQ from 25 visual puzzles in about 12 minutes.
| Percentile | 96.9 |
| Share scoring 128 or higher | 3.1% (about 1 in 32) |
| Out of 1,000 people | about 31 at or above |
| Standard deviations from the mean (z) | +1.87 |
| WAIS-IV classification | Superior (120 to 129) |
| Same percentile, SD 16 scale | 130 |
| Same percentile, SD 24 scale | 145 |
What an IQ of 128 means on the scale
Modern IQ tests report a deviation IQ: scores are standardized so the mean is 100 and the standard deviation is 15 within each age group (Wikipedia: Intelligence quotient). On that scale 128 is 1.87 standard deviations above the mean. It is outside the 85 to 115 range that holds about 68% of people, but inside the 70 to 130 range that holds about 95%. (the 68-95-99.7 rule)
In a room of 30 people your age, about 1 would be expected to score 128 or higher. Put another way, about 97 out of every 100 people score below 128.
The Superior band: 120 to 129
The WAIS-IV labels 120 to 129 as Superior (Wikipedia: IQ classification): clearly above average, between about one and a third and two standard deviations above the mean. About 7.2% of people score in this band, so it is smaller than High Average below it but far larger than the open-ended Very Superior band above it.
The band runs right up to two thresholds people often ask about. Very Superior starts at 130, and Mensa's line, the 98th percentile, falls at about 131 on a scale with standard deviation 15 (Mensa International). From 128, that is 3 points away. Measurement error on clinical tests is around plus or minus 5 points (Wechsler, 2008), so for the upper half of this band the true score could sit on either side of those lines.
Where 128 sits inside the band
128 is 8 points above the floor of the Superior band (120) and 1 point below its ceiling (129). Of the people who score in this band, about 88% score below 128, so it is near the top of the group that shares its label.
Clinical IQ scores carry measurement error of around plus or minus 5 points at 95% (Wechsler, 2008). A measured 128 is consistent with a true score anywhere from 123 to 133, which is the 93.7 to 98.6 percentile. That range spans two labels, Superior and Very Superior, so the band name is the least certain part of the result. A short online test has a wider range than a clinical one, so read any single number as the middle of a span.
What an IQ of 128 does and does not predict
At this level, the research links higher scores with better average outcomes in school and work, but the links are correlations across many people. They do not tell you how any one person with a 120-something will do.
Across large groups, the links are real. General intelligence at age 11 correlated 0.81 with exam results at 16 in about 70,000 English children (Deary, Strand, Smith & Fernandes, 2007), a review of 85 years of workplace research put the link with job performance at 0.51 (Schmidt & Hunter, 1998), and a 2007 meta-analysis found correlations of about 0.56 with education and 0.23 with income (Strenze, 2007). Those describe tendencies across many people. None of them let anyone predict an individual life from one number. The guide to what IQ predicts explains what a correlation of that size means.
Same score, different tests
Older Stanford-Binet forms used a standard deviation of 16, and the Cattell Culture Fair III scale uses 24 (Wikipedia: IQ classification). The same percentile as 128 on a standard-deviation-15 test reads as about 130 on the first and 145 on the second, so check which scale a number is on before comparing scores from different tests.
Nearby scores
| IQ | Percentile | Rarity | Classification |
|---|---|---|---|
| IQ 115 | 84.1 | 1 in 6 | High Average |
| IQ 120 | 90.9 | 1 in 11 | Superior |
| IQ 125 | 95.2 | 1 in 21 | Superior |
| IQ 126 | 95.8 | 1 in 24 | Superior |
| IQ 127 | 96.4 | 1 in 28 | Superior |
| IQ 129 | 97.3 | 1 in 38 | Superior |
| IQ 130 | 97.7 | 1 in 44 | Very Superior |
| IQ 131 | 98.1 | 1 in 52 | Very Superior |
| IQ 135 | 99.02 | 1 in 100 | Very Superior |
| IQ 140 | 99.62 | 1 in 260 | Very Superior |
IQ 127 · IQ 129 · every score on the IQ chart · IQ percentile calculator · the seven classification bands
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
- Wechsler, D. (2008). WAIS-IV Technical and Interpretive Manual. Pearson.
- Deary, I. J., Strand, S., Smith, P., & Fernandes, C. (2007). Intelligence, 35(1), 13-21. doi.org/10.1016/j.intell.2006.02.001
- Schmidt, F. L., & Hunter, J. E. (1998). Psychological Bulletin, 124(2), 262-274. doi.org/10.1037/0033-2909.124.2.262
- Strenze, T. (2007). Intelligence, 35(5), 401-426. doi.org/10.1016/j.intell.2006.09.004
- About us. Mensa International. www.mensa.org/mensa/about-us