Short answer: Srinivasa Ramanujan (1887–1920) never took an IQ test, and no psychologist has published a scholarly estimate of his IQ. The 185 repeated online has no documented source. The closest thing to a score is a rating: G. H. Hardy ranked mathematicians for natural talent from 0 to 100, gave himself 25, J. E. Littlewood 30, David Hilbert 80 — and Ramanujan 100.
At a glance
| Estimated IQ | No scholarly estimate; the online figure of 185 is unsourced |
|---|---|
| Basis of estimate | None. No test on record, and he falls outside Catharine Cox's 1926 study (births 1450–1850) |
| Measured score | None on record |
| Hardy's talent rating | 100 on a 0–100 scale (Hardy 25, Littlewood 30, Hilbert 80) |
| Born – died | 22 December 1887, Erode, India – 26 April 1920, aged 32 |
| Field | Number theory, infinite series, continued fractions, partitions |
| Signature achievement | Nearly 3,900 results; the Hardy–Ramanujan partition formula (1918); mock theta functions |
| Comparable minds | Leonhard Euler, Carl Friedrich Gauss |
No test, no Cox entry, one famous rating
Ramanujan died on 26 April 1920, aged 32. The first practical intelligence test, the Binet–Simon scale, appeared in France in 1905; Lewis Terman's Stanford revision followed in 1916, while Ramanujan was working in Cambridge. No record shows that anyone tested him, and no score has surfaced in his letters, his notebooks or the biographies built on them.
The standard scholarly source for historical IQ estimates does not help either. Catharine Cox's Early Mental Traits of Three Hundred Geniuses (1926) rated only people born between 1450 and 1850. Ramanujan, born in 1887, was never in the pool. Any number attached to him is therefore an invention, not an estimate. Our full Ramanujan profile covers his life; how historical IQ estimates work explains the method he falls outside.
Ramanujan's record at a glance
Without a score, the dates carry the argument. Each entry below is documented; together they trace an untrained clerk becoming a Fellow of the Royal Society in five years.
| Date | Event |
|---|---|
| 22 December 1887 | Born in Erode, Madras Presidency |
| 1903 | Obtains Carr's Synopsis, about 5,000 theorems, at 16 |
| 1906–1907 | Fails the First Arts examination twice |
| 16 January 1913 | Writes to G. H. Hardy with more than 120 results |
| April 1914 | Arrives in England to work with Hardy |
| 16 March 1916 | Cambridge BA by research |
| 2 May 1918 | Elected Fellow of the Royal Society |
| 13 October 1918 | Elected Fellow of Trinity College, Cambridge |
| 1919 | Returns to India |
| 26 April 1920 | Dies, aged 32 |
| Spring 1976 | George Andrews finds the lost notebook at Trinity |
Hardy's 0–100 scale: the closest thing to a score
The best evidence of how Ramanujan's mind compared with others comes from the man who knew it best. According to Bruce C. Berndt, the leading editor of Ramanujan's notebooks, Paul Erdős passed on G. H. Hardy's personal ratings. Berndt frames them simply: suppose "we rate mathematicians on the basis of pure talent on a scale from 0 to 100." Hardy gave himself 25. He gave J. E. Littlewood, his longtime collaborator, 30. He gave David Hilbert, the Göttingen mathematician who set the agenda for 20th-century mathematics with 23 problems in 1900, 80. He gave Ramanujan 100.
| Mathematician | Hardy's rating (0–100) |
|---|---|
| G. H. Hardy | 25 |
| J. E. Littlewood | 30 |
| David Hilbert | 80 |
| Srinivasa Ramanujan | 100 |
Read it carefully. This is not an IQ scale. It has no norms, no test items and no standard deviation, and it reached print secondhand, from Hardy to Erdős to Berndt. But it carries a weight no listicle number can. It comes from a leading analyst of his generation who worked with Ramanujan in Cambridge from 1914 to 1919 and knew Littlewood's and Hilbert's work at first hand. Hardy's scale ranks raw talent, the ability training cannot supply. On that measure he put Ramanujan at the ceiling.
Where the 185 comes from, and why it fails
Search for Ramanujan's IQ and one number dominates: 185. It appears across list sites and in a 2024 Reader's Digest roundup, which says he "reportedly had an estimated IQ of 185" and names no source. No psychologist, biographer or historiometric study stands behind the figure. It has simply been repeated until it looks like a fact.
It also fails on arithmetic. On a modern deviation scale (mean 100, standard deviation 15), an IQ of 185 sits 5.67 standard deviations above the mean: roughly one person in 137 million. The WAIS-IV, the standard adult test, cannot report a full-scale score above 160. A claim of 185 for a man who never sat a test is not an estimate with a margin of error. It is a guess with no error bar at all.
The 1913 letter: evidence in his own hand
The real evidence is documentary. On 16 January 1913, a 25-year-old clerk at the Madras Port Trust wrote to Hardy at Trinity College, Cambridge, enclosing more than 120 results across at least 11 pages. He had no degree. He had lost his scholarship at the Government Arts College in Kumbakonam because he neglected every subject but mathematics, and he failed his First Arts examination in December 1906 and again a year later. His training came largely from one book, G. S. Carr's Synopsis of Elementary Results, a compendium of some 5,000 theorems he obtained in 1903, at 16.
Hardy and Littlewood asked themselves whether the sender was "an Euler" or merely "a Jacobi." Of several continued-fraction formulas Hardy later wrote: "They must be true because, if they were not true, no one would have had the imagination to invent them." Not everything held up. Ramanujan's claims about the distribution of prime numbers were wrong. But few letters in the history of mathematics have carried so much that was both new and correct.
Cambridge, 1914–1919: the proof in print
Ramanujan reached England in April 1914. Within five years the outsider had a Cambridge BA by research (March 1916, for work on highly composite numbers); a joint paper with Hardy giving an asymptotic formula for the number of partitions of an integer (1918); election as a Fellow of the Royal Society on 2 May 1918, only the second Indian admitted; and, on 13 October 1918, a fellowship of Trinity College, the first awarded to an Indian. Over his short life he compiled nearly 3,900 results, mostly identities and equations.
The best-known moment shows how he held numbers in mind. Hardy visited him when he was lying ill at Putney and remarked that his taxi, No. 1729, seemed "rather a dull one." Ramanujan replied: "it is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways." That is, 1729 = 1³ + 12³ = 9³ + 10³. The fact was not new. Bernard Frénicle de Bessy had noted it in 1657, and Ramanujan had recorded it in his own notebooks years earlier. Instant recall is the point. Littlewood remarked that "every positive integer was one of his personal friends."
The lost notebook: a final year still being decoded
Ramanujan returned to India in 1919 and died the next spring. In his last year he filled more than 100 loose pages: 138 sides carrying over 600 formulas, listed without proofs. In the spring of 1976 George Andrews of Pennsylvania State University found them among G. N. Watson's papers in the Wren Library at Trinity College. Mock theta functions, a subject Ramanujan introduced in his last letter to Hardy, dominate the pages. Andrews and Berndt published their analysis in five volumes between 2005 and 2018. Read the full story of the lost notebook.
That is the strongest argument against pinning a number on him. An IQ score summarizes performance on a timed test against a norm group. Ramanujan's output is still generating research a century after his death; Quanta Magazine reported in 2024 that his partition identities keep surfacing in fields from algebraic geometry to prime detection. No test was designed to measure that.
Ramanujan vs Einstein, Euler and Gauss
"Ramanujan IQ vs Einstein" is a common search. The honest answer: neither man took an IQ test. The 160 attached to Albert Einstein's IQ is as undocumented as Ramanujan's 185, so subtracting one from the other measures nothing. Their minds also worked in opposite directions. Einstein built physics from a few principles; Ramanujan produced formulas by an intuition he rarely explained, leaving others to supply the proofs. Our Einstein vs Ramanujan comparison sets the two records side by side.
The fairer comparisons are with other mathematicians. Leonhard Euler, the name Hardy and Littlewood reached for in 1913, and Carl Friedrich Gauss also lack Cox estimates, and their online numbers are equally unsourced. What they share with Ramanujan is a documented record of formula-making at extraordinary speed. The ranking of mathematicians by estimated IQ shows who has a real estimate and who does not.
How this page was assessed
We searched for any recorded test, any entry in Cox (1926) and any published historiometric estimate; none exist. We then relied on primary and scholarly accounts: Hardy's own writing, Berndt's editorial work on the notebooks and the MacTutor archive at the University of St Andrews. Hardy's scale is reported as testimony, not measurement. Popular figures appear only to show why they fail.
Frequently asked questions
What was Ramanujan's IQ?
Nobody knows, because Ramanujan never took an IQ test and no scholar has published an estimate. The widely repeated 185 has no documented source. The most credible comparative judgment is G. H. Hardy's private talent scale, relayed by Paul Erdős and Bruce Berndt: Hardy 25, Littlewood 30, Hilbert 80, Ramanujan 100. That rating ranks natural mathematical talent, not IQ.
Was Ramanujan a genius?
Yes, by any standard mathematicians use. Largely self-taught from a single book of theorems, he sent Hardy more than 120 results in 1913, became a Fellow of the Royal Society at 30 and left nearly 3,900 results. His lost notebook, found in 1976, has filled five volumes of commentary published between 2005 and 2018.
Who had a higher IQ, Ramanujan or Einstein?
The question has no factual answer. Neither man took an IQ test, and both popular numbers, 160 for Einstein and 185 for Ramanujan, lack a documented source. Their achievements also differ in kind: Einstein rebuilt physics from first principles, while Ramanujan generated deep formulas by intuition, many of them proved only decades later.
What was Hardy's scale of mathematical talent?
It was an informal 0–100 rating of pure talent that Hardy applied to mathematicians. Paul Erdős passed it on, and Bruce C. Berndt put it in print. Hardy scored himself 25, Littlewood 30, David Hilbert 80 and Ramanujan 100. No norms or test stand behind it, but it records the judgment of Ramanujan's closest collaborator.
How many theorems did Ramanujan produce?
He compiled nearly 3,900 results over his life, mostly identities and equations, and often stated them without proof. Much of the proving was left to others: Bruce Berndt spent decades verifying the entries in his notebooks, and Andrews and Berndt's five-volume edition of the lost notebook appeared between 2005 and 2018.
Why is 1729 called the Hardy–Ramanujan number?
Hardy visited the ailing Ramanujan in Putney in taxi No. 1729 and called the number dull. Ramanujan answered that it is the smallest number that can be written as a sum of two positive cubes in two ways: 1³ + 12³ and 9³ + 10³. Numbers with this property are now called taxicab numbers.
Sources
- Srinivasa Ramanujan — Wikipedia — Dates, exam failures, Royal Society and Trinity fellowships, nearly 3,900 results
- Srinivasa Ramanujan — MacTutor History of Mathematics, University of St Andrews — January 1913 letter, Cambridge BA (1916), FRS confirmation (1918)
- Srinivasa Ramanujan — K. Srinivasa Rao, Institute of Mathematical Sciences, Chennai — Berndt's account of Hardy's 0–100 talent ratings, passed on by Erdős
- Who Was Ramanujan? — Stephen Wolfram (2016) — Letter date and length; 'an Euler' or 'a Jacobi'; Littlewood's remarks
- Srinivasa Ramanujan Was a Genius. Math Is Still Catching Up — Quanta Magazine (2024) — Hardy's 'must be true' remark; continuing influence of his identities
- 1729 (number) — Wikipedia — Hardy's taxicab account; Frénicle de Bessy (1657)
- Ramanujan's lost notebook — Wikipedia — 1976 discovery by George Andrews; pages, formulas and published volumes
- Simonton, D. K. (2020). Galton, Terman, Cox: The Distinctive Volume II in Genetic Studies of Genius. Gifted Child Quarterly — Cox's selection criteria, including births 1450–1850
- 50 People with the Highest IQ Scores — Reader's Digest — Example of the unsourced 185 claim
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.