An IQ score of 128 falls into the Superior range on the standard intelligence scale (mean = 100, standard deviation = 15). This score is notably above average — typically associated with strong academic and professional performance.
What an IQ of 128 means
128 is at about the 97th percentile, so about one person in 32 scores this high or higher. It is the top of the superior band, two points short of the gifted range. A score this near 130 makes the arbitrariness of band boundaries obvious: 128 and 131 differ by less than the error of measurement, yet one is labelled superior and the other gifted. It is more accurate to describe 128 as being at the threshold of the gifted range. If the label matters to you, for instance for a society application, only a supervised test will settle it.
Where does an IQ of 128 rank?
On a standardized IQ test, a score of 128 places you higher than approximately 96.9% of the population. Intelligence scores follow a normal distribution — most people cluster near 100, and scores taper off sharply toward both extremes.
| Metric | Value |
|---|---|
| IQ score | 128 |
| Classification | Superior |
| Percentile | 96.9% |
| Rarity (out of 1,000) | ~31 in 1,000 score this high or higher |
| Standard deviations from mean | 1.87 |
IQ 128 in numbers
- Roughly 1 in 32 people score 128 or higher.
- In a room of 100 randomly chosen adults, about 3 would score 128 or higher.
- That is 2 points below 130, the level most high-IQ societies use as their entry line.
- Another 2 points would move this score into the Gifted band, which starts at 130.
- Even on professionally administered tests a single result has a margin of error of about five points either way, so a measured 128 is best read as somewhere between 123 and 133.
On our free IQ test
Of the 3,834 people who completed our free IQ test between April and October 2026, 72 scored exactly 128 and 15.0% scored higher. People who choose to take an online IQ test are not a random sample of the population (our average is 114.5), so this shows where a score sits among other test-takers, not among everyone. More in our 2026 data study.
Which IQ tests produce a score of 128?
A score of 128 can be produced by any standardized intelligence test that uses the mean = 100, SD = 15 scale. The most widely used tests include:
- Wechsler Adult Intelligence Scale (WAIS) — clinical gold standard for adults.
- Stanford-Binet Intelligence Scales — oldest continuously-used intelligence test.
- Mensa admissions test — used by the Mensa society for membership selection.
- Cattell-Horn-Carroll (CHC) tests — most theoretically grounded modern framework.
- Our free IQ test — instant online estimate with the same scaling.
How to interpret an IQ score of 128
Scores in the high-average to superior range are associated with strong performance in educational and analytical settings. People at this level often report that unstructured problem-solving and abstract learning feel relatively natural, though domain expertise still requires deliberate practice.
IQ 128 in Context
| IQ Range | Classification | Population % |
|---|---|---|
| Below 70 | Extremely Low | ~2.2% |
| 70–79 | Borderline | ~6.7% |
| 80–89 | Low Average | ~16.1% |
| 90–109 | Average | ~50% |
| 110–119 | High Average | ~16.1% |
| 120–129 | Superior | ~6.7% |
| 130+ | Gifted / Very Superior | ~2.2% |
Factors That Influence Your Score
Your IQ score reflects a combination of genetic potential and environmental influences including education, nutrition, health, and the testing conditions themselves. Factors like fatigue, anxiety, unfamiliarity with the test format, and even the time of day can all affect performance. A single test score should be viewed as an estimate, and scores can vary by several points between testing sessions.
Nearby scores
Compare the major IQ tests
Which test produces the most accurate score depends on what you're trying to measure. These head-to-head comparisons break down the differences:
- WAIS vs Stanford-Binet — the two clinical heavyweights compared.
- Mensa vs WAIS — entry-test speed vs full clinical assessment.
- Stanford-Binet vs Mensa — which one actually gets you into Mensa.
- CHC vs Wechsler — modern cognitive framework vs the classic.
- Raven vs Cattell — non-verbal alternatives for cross-cultural testing.
Further reading
- What is a good IQ score?
- What does your IQ score mean?
- Average IQ by age
- Mensa requirements
- IQ test types compared
Want to find out your IQ score?
Take a free, comprehensive cognitive assessment modeled on clinical IQ tests.
Take the Free IQ TestFrequently asked questions
Is IQ 128 considered good?
An IQ of 128 is above average (97th percentile). It's associated with strong academic and analytical performance, though IQ is only one dimension of overall ability.
Can an IQ of 128 change over time?
IQ scores are relatively stable in adulthood but can shift modestly with education, engagement, sleep, and health. Short-term factors like stress and fatigue can move a single test result by 5–10 points in either direction — which is why we recommend comparing results across multiple sessions rather than reading too much into any single score.
What percentile is IQ 128?
An IQ of 128 corresponds to the 96.9th percentile on the standard bell curve — meaning it is higher than about 97 out of every 100 people.