What Is the Highest IQ Score Possible?

On this page

1. What is the highest IQ score?
2. What is the highest IQ score you can get on a test?
3. What is a perfect IQ score?
4. How rare are very high IQ scores?
5. Why do some claims reach 180 or 200?
6. How did IQ scores change from the old formula to the modern one?
7. How big can the same score look on different scales?
8. Who has the highest IQ ever recorded?
9. Is a higher IQ always better?
10. How accurate are scores at the top?
11. FAQ

The IQ scale has no highest score, but every test does. Each test has a ceiling, the top score it can report. The WISC-V full-scale score, for example, runs from 40 to 160⁴. Claims far beyond that, such as 200, do not come from modern norms.

What is the highest IQ score?

The highest IQ score is whatever your test can report. The scale has no top of its own. An IQ is a standard score. It says how far above the average a result sits, in standard deviations. In theory that distance has no end.

Real tests are different. Each one has a ceiling, the highest score its norms allow. The WISC-V, a test for children, reports full-scale scores from 40 to 160⁴. Other tests publish their own ranges in their manuals. We have not read those manuals, so we do not list their numbers here.

On our own free test, the top is much lower. Our test is short, so it runs out of hard questions early. Anything above 145 is shown as “145 or higher”.

What is the highest IQ score you can get on a test?

The highest IQ score you can get on a test is that test’s ceiling. On the WISC-V it is the top of 40 to 160. No answer sheet can produce more, because the norms stop there.

Near a ceiling, scores also get less precise. Our own test shows this clearly. At 100 its 90% range is about 88 to 112, and near the top the range is wider.

So a “perfect” score does not mean “the highest possible ability”. It means the person answered everything the test could ask. Their ability could be at the ceiling or far above it. The test cannot tell.

What is a perfect IQ score?

A perfect IQ score is the score a test gives when every answer is right. It is not a fixed number like 200. It depends on the test and its norms.

On our own test, a perfect answer sheet currently shows about 140. That is below our display ceiling of 145, because our scoring model pulls extreme results toward the middle while its norms are provisional. Our methodology explains this in detail.

On a clinical test, a perfect result lands at or near its ceiling. That is still a real score, but it only sets a floor. The person’s ability could be higher than the test can show.

How rare are very high IQ scores?

Very high IQ scores are extremely rare on paper. On an SD 15 test, a 145 is about 1 in 741 people, and a 160 is about 1 in 32,000. A 200 would be rarer than 1 in 76,000,000,000.

These numbers show why the far top is so hard to measure. A test is normed by comparing people with a norming sample, a large group tested to set the scale. A norming sample would need to be enormous to include even one person at 200. See what a 160 IQ means for the highest score page on this site.

Why do some claims reach 180 or 200?

Claims of 180 or 200 usually come from methods that are not modern IQ scores. There are three common sources. They are the old ratio formula, tests with a wider spread, and pure estimates.

The first is the ratio IQ. Early tests divided mental age by real age and multiplied by 100. This only works for children. It can also produce very large numbers. A 6-year-old who performs like an average 12-year-old gets a ratio IQ of 200. That number is simple arithmetic, not a rank among people. The IQ calculator shows both formulas side by side.

The second is scale. Some tests use a standard deviation of 24 instead of 15. On such a test, the same rank as 145 on an SD 15 test is about 172. A big number can therefore be an ordinary high score on a wider scale.

The third is estimation. Some famous numbers were never measured at all, as the Einstein case shows. They were written by people guessing about someone who never took a test. Mensa’s supervisory psychologist calls claims of 180 or 200 for people who died before tests existed not credible³.

How did IQ scores change from the old formula to the modern one?

IQ scores moved from a ratio of ages to a rank among people. That change explains many old high numbers. Here is the order in which it happened.

First, Binet built the first modern intelligence test to find children who could not keep up at school. He placed each question at the average age at which children could solve it. A child’s result then showed how far ahead or behind their peers they were.

Next, William Stern proposed dividing this mental age by the child’s real age. Terman later multiplied the result by 100 for the Stanford-Binet test. This became the famous intelligence quotient.

Finally, Wechsler solved the problem of scoring adults. He compared each person’s performance with the spread of scores in their age group. That is the deviation IQ used today. Its average is 100.

The ratio formula only works while older age means better abilities. That is true in childhood. So a very high ratio IQ from childhood is a different kind of number from a modern adult score.

How big can the same score look on different scales?

The same rank can look much bigger on a scale with a wider spread. This table shows three high ranks on the three common scales:

So a 196 on an SD 24 scale is the same rank as a 160 on an SD 15 scale. Before you compare two very high scores, check which scale each one uses. The IQ scale page explains the three scales.

Who has the highest IQ ever recorded?

No one can be named with confidence, because no “highest ever” score is backed by a verified test record we could check. We do not print names or numbers we cannot trace to a primary source.

A number on a “highest IQ” list can come from any of the three sources above. Such numbers cannot be compared with each other, or with a modern deviation IQ. Einstein is a good example. There is no evidence he ever took an intelligence test, yet many numbers are quoted for him. Read Einstein’s IQ for where they came from.

Is a higher IQ always better?

A higher IQ means a higher score on reasoning tasks, and that is all a score can say. A 130 already places someone at the 97.72nd percentile, and each point above it adds less and less. It does not measure effort, character or what a person will achieve. Past a certain point, it also stops being measured precisely.

The popular idea of a “genius” score has no official basis either. Our page on what IQ is considered genius explains where the 140 line came from. Mensa uses a lower line, the 98th percentile, and only accepts supervised tests⁵. The Mensa IQ test page explains its rules.

How accurate are scores at the top?

Scores at the top are hard to measure precisely. Every score has a standard error of measurement, the typical amount it would move on a retest. On our own test, the 90% range is widest near the top.

This is one reason to be careful with any very high online score. The page are IQ tests accurate covers measurement error in more depth. Our IQ scale shows where each band starts.

FAQ

What is the max IQ?

There is no maximum IQ on the scale itself. Each test has its own ceiling, such as the top of 40 to 160 on the WISC-V full-scale score.

Is 200 IQ possible?

A 200 is possible as a number on paper, but no modern test can measure it. On an SD 15 scale it would be rarer than 1 in 76,000,000,000. Claims of 200 come from ratio formulas, other scales or estimates.

What is the highest IQ score on an online test?

Each online test sets its own top. Ours shows anything above 145 as “145 or higher”. A perfect answer sheet currently shows about 140.

Is 145 the highest IQ?

No. A 145 is three standard deviations above the average, at the 99.87th percentile. Clinical tests go higher, and the scale itself has no top. See what a 145 IQ means.

What is the lowest IQ score?

The lowest IQ score, like the highest, depends on the test. The WISC-V full-scale score starts at the low end of 40 to 160. Our own test shows anything below 70 as “below 70”.

Who had the highest IQ in history?

No one can be named, because no such score is backed by a record we could verify. Some famous numbers are estimates by writers, not test results, as the Einstein case shows.

Can you take a test to prove a very high IQ?

A formal score comes from a supervised test. Even then, the result is limited by the test’s ceiling. Our free IQ test is an estimate, not proof.