What Was Einstein’s IQ? The Number With No Source

Albert Einstein has no IQ score. Not a disputed one, not an estimated one, not one from an old test on a different scale. There is no record that he ever sat an intelligence test, and the figure of 160 that appears in thousands of articles, quizzes and infographics has no identifiable source.

That is the whole answer. The interesting part is how a number with nothing behind it became one of the most confidently repeated facts about one of the most documented people of the twentieth century.

Did Einstein ever take an IQ test?

There is no evidence that he did, and the timing makes it unlikely.

The first widely administered adult intelligence test was the Army Alpha, developed in 1917 for screening United States military recruits. Einstein was 38 years old that year, living in Berlin, and already internationally known. He published the general theory of relativity in 1915.

Adult IQ testing simply was not a thing that happened to established European physicists in that period. It was a screening tool for armies and schools. By the time the Wechsler scales made adult testing routine in 1939, Einstein was 60 and at Princeton. No result for him has ever surfaced in any archive, biography or correspondence.

Where the 160 came from

Nowhere that anyone has been able to find, and this has been checked properly rather than assumed.

The intelligence researcher Russell Warne set out to trace the origin of every published claim about Einstein’s IQ. He found no evidence that any test was ever administered to Einstein, and no credible source behind any of the figures in circulation. The number has no first appearance that can be identified, no study, no assessor, no document.

What it has instead is repetition. A figure gets printed, then quoted, then quoted from the quotation, and after enough iterations the absence of a source stops being noticeable. The 160 is now embedded in listicles, school worksheets and marketing copy for IQ tests, none of which can tell you where it came from because none of them knows.

It is worth noticing that 160 is also a suspiciously tidy number. It sits exactly four standard deviations above the mean on the modern scale, which is the sort of figure someone reaches for when they want to convey “extremely high” rather than the sort that comes out of an actual assessment.

The study people assume it came from

When pressed for a source, people often point to Catherine Morris Cox’s 1926 study, which retrospectively estimated IQs for eminent historical figures from biographical records. It is the origin of many of the historical IQ numbers in circulation, so the assumption is reasonable.

It is also wrong. Cox studied 301 eminent figures born between 1450 and 1850. Einstein was born in 1879. He is not in the study, and could not have been: he was 47 and very much alive when it was published.

Cox’s method is worth understanding anyway, because it explains what every historical IQ figure actually is. She and her colleagues read biographical accounts of each subject’s childhood, looked for documented early achievements and intellectual milestones, and estimated what IQ would have been consistent with that record. It was a serious piece of work for its time and a legitimate research method with a name, historiometry. What it was not was measurement, and the researchers did not present it as such.

Which means historical IQ figures have a built-in bias nobody mentions: they reward people whose childhoods happened to be well documented. Someone whose early brilliance was recorded in letters and journals scores higher than someone equally able whose childhood left no paper trail.

And no, he did not fail maths

Worth dealing with while we are here, because it is the mirror image of the IQ myth and just as durable.

Einstein was strong at mathematics from early on and had worked through calculus by around fifteen. The claim that he failed the subject appears to come from two sources tangled together. The Swiss grading scale was reversed at one point during his schooling, so a set of marks that looks poor on one reading is excellent on the other. And he did fail an entrance examination for the Zurich Polytechnic at sixteen, on the general and language sections, while scoring highly in maths and physics. He was also two years below the normal entry age at the time.

Both myths survive for the same reason: they are appealing. One says genius is quantifiable and enormous. The other says even geniuses fail at school, so do not worry. Neither is true, and they contradict each other, which does not appear to slow either of them down.

The other historical IQs are invented too

If you have seen a chart ranking Newton, da Vinci, Goethe, Mozart and Einstein by IQ, every number on it is either a Cox-style historiometric estimate or something with even less behind it.

None of those people took an IQ test, because none of them lived when such a test existed. The earliest recognisable intelligence test, Binet’s, dates from 1905. Everyone on those charts who died before then was assigned a number by someone reading about their childhood, centuries after the fact.

The same is true at the other end of the scale. Figures circulating for living people with famously high scores are mostly childhood assessments, extrapolations or unverified claims, as set out in our guide to the highest IQ ever recorded.

What this tells you about IQ claims generally

The Einstein case is a useful test of a simple rule: an IQ figure without a named test and a date is not information.

Applied consistently, that rule eliminates almost every celebrity and historical IQ you will encounter. It also eliminates a good deal of marketing copy, since “higher than Einstein’s” is a popular claim for online tests to make about their own results, and it is comparing a real score to a number that does not exist.

There is a broader point underneath it. Einstein’s reputation does not rest on a score and never needed one. It rests on four papers published in 1905 and on general relativity a decade later. Whatever cognitive machinery produced those, the interesting evidence is the work itself, which is documented in enormous detail, rather than a two- or three-digit number that nobody can source.

He seems to have thought something similar. Writing to Carl Seelig in 1952, he put his own account of it plainly: “I have no special talent. I am only passionately curious.”

Frequently asked questions

The bottom line

Einstein’s IQ is unknown and unknowable. He never took a test, the 160 has no traceable source, and it does not come from the 1926 study people assume it comes from, since that study covered figures born between 1450 and 1850 and he was born in 1879.

The useful takeaway is the rule rather than the fact: if a quoted IQ does not come with a named test and a date, it is not a measurement. That applies to historical figures, to celebrities, and to any marketing that invites you to compare your result with a physicist who was never assessed.