Einstein's IQ: The Number That Was Never Measured

Was Einstein ever given an IQ test?

Almost certainly not. The intelligence researcher Russell Warne went looking for the origin of every published claim about Einstein's IQ and found no evidence that any test was ever administered to him, and no credible source behind any of the numbers.

The chronology alone makes it improbable. Binet and Simon's scale, published in 1905, was designed for schoolchildren. The first practical test of adult intelligence was the Army Alpha, developed for US military selection in 1917. Einstein was born in 1879, which made him thirty-eight in 1917 — a professor in Berlin, four years past special relativity's general form, and with no conceivable reason to sit an American army classification exam.

Where did the number 160 come from?

Nowhere anyone can point to. That is the finding. The figure appears in books, in quiz sites and in newspaper columns without a citation attached, and when the citations are chased they lead to other uncited assertions.

Warne traces one representative example: the psychologist Brian M. Hughes stated in his 2018 book Psychology in Crisis that “Einstein's IQ was 160,” and offered no supporting reference. That is the pattern throughout — the number is repeated by people who assume someone else has checked.

What makes 160 particularly hard to defend is that it is not even the traditional figure. Before the internet settled on it, American magazines published wildly different numbers.

A number that drifts from 207 to 160 over sixty years, with no measurement behind any of its values, is not an estimate. It is folklore with a decimal point.

The one serious attempt to estimate a genius's IQ

There is a legitimate research tradition here, and it is worth separating from the trivia. In 1926 Catharine Morris Cox, working at Stanford under Lewis Terman, published the second volume of Genetic Studies of Genius. She assembled roughly 1,500 biographical sources on 301 eminent figures and, from documented childhood behaviour and achievement, assigned each of them an estimated IQ. The method is called historiometry, and it descends from Francis Galton.

Two things about that study are consistently misreported.

1. Einstein is not in it. Cox's sample consisted of people born between 1450 and 1850. Einstein was born in 1879 and was very much alive — aged 47 — when the book was published. The method that could in principle have been applied to him never has been.
2. Cox's numbers are ratio IQs, not deviation IQs. A ratio IQ is mental age divided by chronological age, multiplied by 100 — the scoring used by the 1916 Stanford–Binet. Deviation IQ, introduced by David Wechsler in 1939, instead expresses a score as a position within a normal distribution. The two are different quantities that happen to share a scale name.

Cox's estimates also correlate suspiciously well with how much documentation survived about each subject's childhood — a well-known limitation. Figures with abundant records of precocity scored higher. That is a fact about archives, not about minds.

Why nobody's IQ is meaningfully 160

Set Einstein aside for a moment. The claim “my IQ is 160” has a statistical problem regardless of whose IQ it is.

Modern IQ scores are deviation scores. An IQ of 100 is the population mean and 15 points is one standard deviation. A score of 160 is four standard deviations above the mean, which corresponds to roughly one person in 31,500.

Now consider how a test is normed. A publisher administers it to a standardisation sample — typically a few thousand people, stratified to represent the population. In a sample of 3,000, the expected number of people scoring at or above 160 is about one tenth of one person. In other words: nobody. The test has no observed data at that level. Any score printed up there is extrapolation from the shape of a curve, not measurement of anyone.

Extended norms exist for some instruments and push the reportable range higher, but they rest on small numbers of very high scorers and are correspondingly imprecise. Reporting a four-sigma score to three significant figures implies a precision that no standardisation sample supports.

Did Einstein fail mathematics at school?

No. This is the mirror image of the IQ myth, and it is just as false.

The story appears to have entered circulation through a Ripley's Believe It or Not column in 1935. Einstein saw it and rejected it directly, saying that he never failed in mathematics and that before he was fifteen he had mastered differential and integral calculus. His surviving school records support him: his 1896 matriculation certificate from the cantonal school at Aarau shows top marks in algebra, geometry and physics.

There is a real event underneath the myth. In 1895, aged sixteen and two years younger than the other candidates, Einstein sat the entrance examination for the Zurich polytechnic. He did not pass. He performed outstandingly in mathematics and physics and fell short in the general sections — languages, botany, zoology. He spent a year at Aarau and was admitted the following year.

I never failed in mathematics. Before I was fifteen I had mastered differential and integral calculus.— Albert Einstein, responding to the 1935 claim that he had failed the subject

Both myths serve the same purpose. One flatters the idea that genius is a number you are issued at birth; the other flatters the idea that it is invisible to every measurement. Neither survives contact with the record.

Would knowing Einstein's IQ tell us anything?

Less than people expect. IQ predicts a great deal at the level of populations and comparatively little about any one person's peak achievement.

Whatever Einstein's reasoning ability was, it was not the scarce ingredient. Very high intelligence is rare but it is not that rare: there are, on any reckoning, tens of thousands of people alive today with cognitive ability at or beyond anything a test could have measured in him. Almost none of them will rewrite physics. What distinguished Einstein was a specific, sustained obsession with a specific set of problems, twenty years of unfashionable persistence, and a willingness to take seriously a contradiction that other capable physicists had chosen to work around.

Lewis Terman's longitudinal study is the case most often cited here. From 1921 he followed more than 1,500 children selected for an IQ of roughly 140 or above, across their entire lives. They did well — better than average on almost every measure. None produced work of Einstein's significance. Two boys screened during recruitment, William Shockley and Luis Alvarez, did not clear the threshold and were left out. Both later won the Nobel Prize in Physics.

The defensible statement is narrower and more useful. A high IQ raises the probability of exceptional work without coming close to guaranteeing it, and the traits that convert ability into achievement — persistence, taste in problems, tolerance for being wrong in public — are not what an intelligence test samples.

Myths and facts about Einstein's IQ