What was Einstein's IQ?
No one knows. We found no record that Albert Einstein ever took an IQ test, and the numbers that circulate, such as 160, come without any source of measurement. He is also not in Catharine Cox's 1926 study, which estimated the IQ of historical figures.
In this article
Where does the number 160 come from?
From lists on the internet. The value is repeated on many sites, almost always without saying who gave the test, when, and which instrument was used. We searched and found no published record of an IQ test taken by Einstein. A number without those three facts is not a measurement: it is someone's estimate, or a guess.
If a record with a date and an instrument ever appears, it will change this answer. Until then, the honest answer is that Einstein's IQ is unknown.
Why is Einstein not in Cox's study?
The most cited source for the IQ of historical figures is Catharine Cox's 1926 book. Cox estimated the IQ of people born between 1450 and 1850 by reading biographies, letters and records of their childhood and youth. Einstein was born on March 14, 1879, in Ulm, Germany, according to his biography on the Nobel Prize website. He fell outside the sample.
How Cox worked, and why the numbers attributed to her online are usually higher than those in the book, is explained in How Catharine Cox estimated the IQ of historical figures in 1926.
Could his IQ be estimated today?
Not reliably. A modern IQ is a position relative to people of the same age, obtained by giving a test. A test cannot be given to someone who has died. What remains is Cox's method of reading records and estimating, and her own study shows its limit: the average reliability of the data was close to 0.5 on a scale from 0 to 1.
An intellectual achievement does not convert into an IQ either. One is an accomplishment; the other is a position on a normed test. They go together on average, but one does not tell you the other. The numbers behind that relationship are in Does a high IQ guarantee success?
What can be said with confidence?
What is documented. Einstein received the 1921 Nobel Prize in Physics, according to the Nobel Foundation, for his services to theoretical physics and especially for his discovery of the law of the photoelectric effect. That has a source, a date and a stated reason.
At IQNorth, we show historical figures only with the youth estimate from Cox's book, with the method explained next to it. Einstein is not on that list, for the same reason as this page: the book has no estimate for him.
See also: Historical figures.
Sources
- Cox, C. M. (1926). Genetic Studies of Genius, Vol. II: The Early Mental Traits of Three Hundred Geniuses. Stanford University Press.
- Nobel Foundation. Albert Einstein, biographical. Accessed Nov 5, 2026. https://www.nobelprize.org/prizes/physics/1921/einstein/biographical/
- Nobel Foundation. The Nobel Prize in Physics 1921. Accessed Nov 5, 2026. https://www.nobelprize.org/prizes/physics/1921/summary/
