Napoleon's IQ: The Cox Estimate and the Evidence Behind It

What Catharine Cox Found

The only scholarly numbers for Napoleon come from one book: Catharine Cox's The Early Mental Traits of Three Hundred Geniuses, Volume II of Lewis Terman's Genetic Studies of Genius (Stanford University Press, 1926). Cox read biographies, school reports and letters for 301 eminent people born between 1450 and 1850. Three raters, Cox, Terman and Maud Merrill, then converted each record into an IQ on the scale of the Stanford revision of the Binet-Simon test.

Each person received two figures. A1 covers birth to 17; A2 covers 17 to 26. Napoleon's case appears in her chapter of people rated 130 to 140 for childhood. His figures: A1 = 135, A2 = 140. Cox also computed corrected scores, because thin records pull an estimate toward the average. Secondary tabulations of those corrected figures give Napoleon 145.

For what those scores mean in a modern population, see IQ 135 and IQ 140. For the full career, see our Napoleon Bonaparte profile. For how such numbers are built, and where they break, read historical IQ estimates explained.

The Schoolboy Behind the 135

Napoleon entered the royal military school at Brienne-le-Château in May 1779, aged nine. The Fondation Napoléon's review of his reports is blunt: so-so results in French and Latin, excellent results in mathematics and history. One examiner wrote that he "has always been distinguished for his application in mathematics."

In the autumn of 1784 he moved to the École Militaire in Paris. He left about a year later, in 1785, the first Corsican to graduate, and was commissioned a second lieutenant of artillery at 16. His final rank was 42nd of 58. The Fondation calls those results "mediocre to say the least."

This is the record Cox had to rate. It shows a fast learner, a compulsive reader and a strong mathematician. It does not show a prodigy. For comparison, the only person in her top childhood band, 190 to 200, was the philosopher John Stuart Mill.

Where the 160 and 180 Figures Come From

Online, Napoleon's IQ appears as 145, 160 and even 180. Only the first has a traceable source: Cox's corrected figure. The higher numbers sit on quiz pages and listicles with no named rater, no method and no citation. Even some IQ-test marketing sites concede that the 180 claims lack any credible methodology.

They fail for three reasons. No one can test a man who died in 1821. The only systematic attempt, Cox's, landed between 135 and 145. And the inflated figures reason backward from fame: a man who conquered most of Europe must have had a spectacular score. Cox's data cut against that assumption. Across her 301 subjects, military leaders scored lowest of any field, as the psychologist Dean Keith Simonton noted in a 2020 review of her work.

The Evidence of the Mind

The career supplies what the school reports lack.

• 1793, Toulon. His handling of the artillery at the siege won him promotion to brigadier general at 24.
• 1796–97, Italy. The Army of Italy won 18 pitched battles and took some 150,000 prisoners.
• 1797, the Institut. France's national academy elected him to the seat vacated by Lazare Carnot, the mathematician purged in the Fructidor coup.
• 1798–99, Egypt. He took 167 scientists with the army. The expedition uncovered the Rosetta Stone.
• 1804, the Civil Code. Four jurists drafted it; Napoleon chaired 55 of the commission's 107 plenary sessions. Promulgated on 21 March 1804, it influenced law from Louisiana and Quebec to Romania.
• 1805, Austerlitz. On 2 December he routed the Russian and Austrian armies. He later said: "The battle of Austerlitz is the finest of all I have fought."

The pattern is range: artillery mathematics, legal drafting, logistics across a continent, patronage of science. Range is exactly what a single IQ number compresses worst.

Napoleon Against Alexander, Caesar and Washington

Napoleon is one of very few great commanders with a Cox figure, because he was born inside her 1450–1850 window. Alexander the Great and Julius Caesar lived nearly two millennia too early; neither has any scholarly estimate. George Washington does. Cox rated him 125 and 135, ten points below Napoleon at both ages.

On paper, then, Napoleon outranks Washington and cannot be scored against the ancients at all. Our head-to-head pages weigh the careers instead: Napoleon vs. Alexander and Napoleon vs. Caesar. The full table sits in military leaders ranked by IQ.

What 140 Cannot Explain

An IQ estimate describes the capacity to learn and reason. It says nothing about judgment under pressure, appetite for risk or the discipline to stop. Napoleon's career shows abundant evidence of the first two and little of the third. The 1812 invasion of Russia wrecked the Grande Armée. Waterloo, on 18 June 1815, ended the empire.

Original science is the other gap. The mathematician Étienne Ghys, reviewing Napoleon's seat at the Institut, judges his scientific contributions non-existent. Napoleon admired science, funded it and used it. He did not produce it. Cox's 135 to 140 fits that profile: a quick, broad, practical intelligence rather than an original theorist.

How We Assessed This

We used only figures traceable to Cox's 1926 volume or to peer-reviewed work built on it, and we did not blend them with internet claims. Retrospective estimates carry wide error. For the presidents Cox rated, her reliability corrections added anywhere from 5 points (Washington) to 30 points (James Madison's childhood figure). Treat any historical IQ as a range, never a measurement.

Editorial standard: IQ figures for historical figures are retrospective estimates and are labeled as such; scores for living people appear only when the person disclosed them or a reputable outlet reported them. Corrections: contact the editors.