How rare is an IQ of 128?
Yes. An IQ of 128 is in the superior range, called very high on current children's tests. It is well above average and higher than about 9 in 10 people.
Where 128 sits on the bell curve
An IQ of 128 is 28 points above the average of 100, or 1.87 standard deviations. It is higher than about 97% of people of the same age, shown by the shaded area below. This is the thinning right shoulder of the curve, where only about 1 person in 15 scores in the whole 120 to 129 band.
On other IQ scales, the same result would be about 130 on a test with a standard deviation of 16, such as older editions of the Stanford-Binet, and 145 on the Cattell scale, which uses 24. Why scales differ.
IQ 128 meaning: a closer look
An IQ of 128 is higher than about 97% of people, and roughly one in 32 score this high or above. It is two points below 130. In practice that small gap means a lot to people interested in Mensa, but no IQ test measures precisely enough to separate 128 from 130 on a single attempt. If your online result was 128 and you are curious, an approved supervised test is the only way to find out where you really stand.
Glasses and brains: why near-sightedness is linked with higher IQ
The idea that clever children need glasses has some data behind it. A 2004 study of 1,204 Singapore schoolchildren aged 10 to 12 found that those in the top quarter for nonverbal IQ, measured with Raven's matrices, had 2.4 times the odds of myopia of those in the bottom quarter, even after allowing for reading, parental myopia and father's education. In a 2017 study of more than 1,500 teenage twins, the correlation between refractive error and intelligence was small, about 0.12 in size, and most of that overlap was explained by shared genetic factors.
An IQ of 128 does not mean you will become short-sighted, and wearing glasses says very little about anyone's intelligence. The link is a statistical tendency in large groups, and its causes are still being untangled. Shared genes appear to play a part, and schooling is another strong candidate: a 2018 BMJ analysis of 67,798 UK Biobank participants suggested that each extra year of education causes a slightly more myopic eye. So for someone with a 128 IQ, years of study may explain part of the link rather than the score itself.
Sources: Saw et al. (2004), "IQ and the association with myopia in children", Investigative Ophthalmology & Visual Science; Williams et al. (2017), "Phenotypic and genotypic correlation between myopia and intelligence", Scientific Reports; Mountjoy et al. (2018), "Education and myopia: assessing the direction of causality by mendelian randomisation", BMJ.
What 128 looks like among real people
If you lined up 100 people of your age, about 97 would score lower than 128 and about 3 would score the same or higher. The orange dot marks your place in the line.
In most groups of a few dozen people, a score like this would be among the highest.
How precise is a score of 128?
No IQ test measures to the exact point. On a professional test, a result of 128 usually comes with a likely range of about five points either way: 123 to 133. That range runs from the 94th to the 99th percentile, and it crosses from superior into very superior.
At this level, a single test can place you a few points either side of a line that some people care about, such as 130. A full professional test, or a retest, is the only way to know which side you are on.
On the Assessivo test, 128 is the score for 29 correct answers out of 36. How our score is worked out.
So if you scored 128 once, a retest on another day could reasonably land anywhere from 123 to 133. Online tests are less precise still, so treat any online result as a rough estimate.
IQ 128 and mental age in children
Early IQ tests for children worked with a "mental age", the age whose typical performance a child matched. The IQ was that mental age divided by the child's real age, times 100. Turned around, the formula shows what a score of 128 would have meant for children of different ages: working ahead of their years.
| Real age | Mental age at IQ 128 |
|---|---|
| 5 | 6 years 5 months |
| 7 | 9 years |
| 9 | 11 years 6 months |
| 11 | 14 years 1 month |
| 13 | 16 years 8 months |
The same 128 stands for a gap of about 1 year 5 months at age 5 but 3 years 8 months at 13, because the formula scales with age. That is one reason it broke down for teenagers and adults, whose test performance stops rising every year. Today's tests compare you with people of the same age instead, so a mental age is only a way to picture a child's score, never a description of an adult.
What an IQ of 128 means for you
It sits near the top of the superior band, which runs from 120 to 129.
- You likely solve unfamiliar problems quickly and handle complex, abstract information well.
- Demanding academic and technical work often suits people in this range, although many other qualities decide success.
- It is below the 130 level that Mensa usually requires, but within reach of it on a good day or a different test.
How far 128 is from other levels
How 128 compares with nearby scores
Want a score that isn't listed, or the share of people between two scores? Try the IQ calculator.
| IQ | Percentile | Classification | Score this high or higher |
|---|---|---|---|
| 118 | 88th | High average | 1 in 9 |
| 123 | 94th | Superior | 1 in 16 |
| 128 | 97th | Superior | 1 in 32 |
| 133 | 99th | Very superior | 1 in 72 |
| 138 | 99.4th | Very superior | 1 in 177 |
Questions about an IQ of 128
What percentile is an IQ of 128?
An IQ of 128 is at about the 97th percentile, which means it is higher than about 97% of people of the same age.
Is 128 a high IQ?
It is well above average. Most definitions reserve "high IQ" for 130 and above, but 128 is higher than about 97% of people.
Can an IQ of 128 get into Mensa?
Not on its own. Mensa accepts the top 2% on an approved, supervised test, which is usually 130 or above. 128 is 2 points below that.
How common is an IQ of 128 or higher?
About 3% of people score 128 or higher, roughly 1 in 32. In a stadium of 50,000 people, about 1,550 would score at this level or above.
Are people with a 128 IQ more likely to need glasses?
Slightly, on average. Studies in Singapore and the UK found near-sightedness somewhat more common among children and teenagers with higher IQ scores, but the link is small. Shared genes and more years of education seem to explain part of it. Many people with a 128 IQ have perfect eyesight, and glasses say little about intelligence.
What mental age is an IQ of 128?
Under the old ratio formula, a 9-year-old with an IQ of 128 would perform like a typical child of about 11 years 6 months, roughly 30 months ahead. The idea only works for children: an adult who scores 128 simply did better than most adults of the same age on the test.
Is an IQ of 128 very high?
It is high: higher than about 9 in 10 people. Current children's tests label 120 to 129 very high. Most people reserve "very high" or "gifted" for 130 and above.
Can an IQ of 128 change?
A measured score can move a few points between tests because of measurement error and practice, so a result in the 120s on one test may come out higher or lower on another. Large, lasting changes are uncommon in adults, whose scores are usually stable over many years.
Is 128 good for a scientist or engineer?
It is a strong score for demanding technical work, but there is no IQ requirement for any profession. Training, persistence and curiosity matter at least as much.
See where 130 and the other benchmarks sit in what is a good IQ score?, and what higher scores do and don't predict in what IQ is. Average scores by occupation are on our IQ by profession page. Every score range is in the IQ range chart.
An IQ test arrives at a score like 128 by combining several kinds of task. Learn more about verbal reasoning, processing speed, fluid vs crystallized intelligence, abstract reasoning and spatial reasoning, or try the free pattern recognition test.
What would you score?
Take the free Assessivo IQ test: 36 questions, 25 minutes, and your estimated IQ score and percentile as soon as you finish.
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