Short answer: An IQ of 128 is superior: higher than about 97 percent of people, roughly 1 in 32. It sits 1.87 standard deviations above the mean, in the Wechsler Superior band (120–129). It falls two points below Mensa's line of 130 on SD 15 tests. The same performance reads 130 on an SD 16 scale, which still misses that scale's Mensa cutoff of 132.
Shaded: the share of people who score higher on a mean-100, SD-15 scale.
At a glance
| Percentile | 96.9th |
|---|---|
| Rarity | About 1 in 32.3 (3.1 percent score 128 or higher) |
| Wechsler classification | Superior (WAIS-IV) / Very High (WAIS-5) |
| Stanford-Binet 5 classification | Superior |
| On an SD 16 scale | 130 |
| On an SD 24 (Cattell) scale | 145 |
| Mensa eligible? | No. Mensa's lines are 130 (SD 15), 132 (Stanford-Binet, SD 16) and 148 (Cattell) |
What an IQ of 128 means
A 128 is 28 points above the average of 100, or 1.87 standard deviations. It outscores about 97 of every 100 people. In a company of 500 employees, about 15 would be expected to match or beat it.
Wechsler tests label the range from 120 to 129 Superior on the WAIS-IV and Very High on the WAIS-5. The Stanford-Binet 5 also calls it superior. Both reserve their next band for 130 and up. Our IQ classification guide shows where each band starts.
How rare is 128?
| IQ | Percentile | Share at or above | Rarity |
|---|---|---|---|
| 123 | 93.7 | 6.3% | 1 in 16 |
| 125 | 95.2 | 4.8% | 1 in 21 |
| 128 | 96.9 | 3.1% | 1 in 32 |
| 130 | 97.7 | 2.3% | 1 in 44 |
| 135 | 99.0 | 0.98% | 1 in 102 |
The step from 128 to 130 cuts the qualifying share from about 3.1 percent to 2.3 percent. That gap, less than one percentage point, separates a superior score from a Mensa score. The wider curve is on our IQ rarity chart.
Why a 128 can look like a 130
Scales differ in spread. A 128 on a Wechsler test, with standard deviation 15, sits at the same rank as a 130 on older Stanford-Binet editions, which used 16, and a 145 on the Cattell scale, which uses 24.
That is why Mensa lists a separate cutoff for each: 130 for Wechsler tests, 132 for the Stanford-Binet and 148 for the Cattell. Someone reporting "130 on the Stanford-Binet" has the same standing as a Wechsler 128, and neither qualifies. The rank decides, not the digits. Our Mensa admission guide explains which tests count.
Is 128 a good IQ? The workplace evidence
It is a high score, and the research on jobs shows why it helps without deciding everything. For decades, the standard reference was Frank Schmidt and John Hunter's 1998 review, which put the validity of general mental ability tests for predicting job performance at .51.
A 2022 reanalysis in the Journal of Applied Psychology by Paul Sackett and colleagues argued that earlier corrections for range restriction were too aggressive. Their revised estimate for cognitive ability was .31. That still makes ability a useful predictor, though in their ranking it trailed structured interviews (.42) and job knowledge tests (.40).
For a person at 128, the takeaway is modest. Higher ability tends to help in complex work, on average. Conscientiousness, skill and experience carry much of the rest.
Two points short: is a retest worth it?
Measurement error cuts both ways. Modern tests report 95 percent confidence intervals about ten points wide, so a 128 most likely reflects a true score between about 123 and 133. Allowing for regression toward the mean, the chance that the true score is 130 or higher is roughly one in five.
A retest on a different accepted instrument is legitimate, but practice effects make the second number less informative: a 2018 meta-analysis found average gains of about five IQ points on a repeat attempt. A result that crosses 130 on the second try shows familiarity as much as ability.
Getting a dependable number
Use an individually administered test such as the WAIS-IV, WAIS-5 or Stanford-Binet 5, given by a qualified examiner, and keep the full report. Our free IQ test is a practice screener, not a qualifying result. See why online IQ tests vary, and read what counts as a high IQ for the wider picture.
Neighboring scores
Frequently asked questions
Is 128 a high IQ?
It is superior, the band just below very superior. It outscores about 97 percent of people. Most definitions of a high IQ begin at 130, so 128 sits right at the edge of that label.
What percentile is an IQ of 128?
An IQ of 128 is at about the 96.9th percentile on a scale with mean 100 and SD 15. Roughly 3.1 percent of people score 128 or higher, or about 1 in 32.
Can I get into Mensa with a 128?
Not with a 128 on an SD 15 test. Mensa admits the top 2 percent, which is 130 on Wechsler-type scales. Some applicants qualify later through a different accepted test, but a two-point shortfall is real on the scale that produced it.
Is a 128 IQ good for a professional career?
It is a strong asset. Cognitive ability predicts job performance, with validity estimates between .31 and .51 depending on the method. Many other factors, from training to temperament, shape how any one career unfolds.
Why does my 128 show as 130 on another chart?
The chart likely uses a standard deviation of 16, as older Stanford-Binet editions did. On that scale, the same rank reads 130. Always check the scale before comparing scores; the percentile, about 96.9, stays the same.
Sources
- IQ classification — Superior band 120-129
- Mensa International — Cutoffs 130 Wechsler, 132 Stanford-Binet, 148 Cattell
- Schmidt & Hunter (1998) meta-analysis summary — GMA validity of .51
- Is Cognitive Ability the Best Predictor of Job Performance? (HumRRO, on Sackett et al., 2022) — Revised validities: structured interviews .42, job knowledge .40, cognitive ability .31
- Scharfen, J., Peters, J. M., & Holling, H. (2018). Retest effects in cognitive ability tests: A meta-analysis. Intelligence, 67 — Practice gains on repeat testing
- Intelligence quotient — Confidence intervals of about ten points
Editorial standard: IQ figures for historical figures are retrospective estimates and are labeled as such; scores for living people appear only when the person disclosed them or a reputable outlet reported them. Corrections: contact the editors.
