What Was Srinivasa Ramanujan's IQ?

Srinivasa Ramanujan never took an IQ test, so he has no IQ score. Numbers like "185" that circulate online are inventions with no test record behind them. What the record does show is arguably the most extreme documented mathematical talent in history: a self-taught clerk from Madras who became a Fellow of the Royal Society at 30, and whom G. H. Hardy privately rated 100 out of 100 for pure talent while giving himself a 25. This article explains why no real score can exist, where the 185 claim comes from, and what the verified record of Ramanujan's genius actually looks like.

Ramanujan was born on 22 December 1887 in Erode, Tamil Nadu, India, and died on 26 April 1920 in Kumbakonam at age 32. Practical intelligence testing barely existed in his lifetime; the first Binet scales appeared between 1905 and 1916, and nothing in the biographical literature connects Ramanujan to any of them. There is no test record, no score report, and no examiner account anywhere.

The "185" attached to his name lives only on aggregator listicles that cite no primary source. It could not have come from a modern instrument in any case: the WAIS-IV, a leading adult test, reports Full Scale IQs from 40 to 160, and no professionally normed test measures beyond that ceiling. Historically, numbers above 160 usually trace to "ratio IQ," Lewis Terman's 1916 formula of mental age divided by chronological age times 100, a scoring system psychology abandoned decades ago. We explain the ceiling problem in our guide to the highest possible IQ. Ramanujan's case is the same problem as Einstein's IQ: a famous genius, and no test record at all.

As a schoolboy at Town High School in Kumbakonam, Ramanujan came across G. S. Carr's Synopsis of elementary results in pure mathematics, a terse compendium of theorems. Working through it, he taught himself mathematics almost entirely alone, then pushed into territory of his own. As he later wrote to Hardy: "I have had no university education but I have undergone the ordinary school course."

In January 1913, while working as a clerk, Ramanujan wrote to the Cambridge mathematician G. H. Hardy after seeing Hardy's 1910 book Orders of Infinity. The letter's pages of unproved theorems convinced Hardy he was reading the work of a mathematician of the highest class. The University of Madras granted Ramanujan a scholarship in May 1913, and in 1914 Hardy brought him to Trinity College, Cambridge, to begin an extraordinary collaboration.

On 2 May 1918 Ramanujan's election as a Fellow of the Royal Society was confirmed, on the proposal of an extraordinary list of mathematicians including Hardy, Littlewood, and Whitehead. On 10 October 1918 he was also elected a Fellow of Trinity College, Cambridge. He worked on the analytical theory of numbers, elliptic functions, continued fractions, and infinite series, and his notebooks are still yielding results a century later.

The most famous glimpse of his mind comes from Hardy himself, in his 1940 lectures: "I had ridden in taxi cab number 1729 and remarked that the number seemed to me rather a dull one... 'No,' he replied, 'it is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways.'" The number 1729 has been known as the Hardy-Ramanujan number ever since.

The closest thing to a rating of Ramanujan's ability comes from his peers rather than a test. According to Paul Erdos, as recorded by the Ramanujan scholar Bruce Berndt, Hardy privately rated mathematicians on a 0 to 100 scale of pure talent: he gave himself a 25, his brilliant collaborator J. E. Littlewood a 30, the great David Hilbert an 80, and Ramanujan a 100. It is an anecdote, and it should be treated as one. It is also the verdict of the man best placed in the world to judge.

This is the honest way to talk about historical genius. IQ tests are valid and reliable when actually administered, and they cannot be administered posthumously. Estimates reverse-engineered from biography are opinions dressed as data, whether the subject is Ramanujan or Isaac Newton. The defensible claim about Ramanujan is "unmeasured, and plainly extraordinary," with the extraordinary part documented beyond dispute.

Nobody knows, because Ramanujan never took an IQ test. No test record, score report, or examiner account exists. Numbers like 185 that circulate online are inventions with no primary source. What is documented is achievement so extreme that Hardy privately rated him 100 out of 100 for pure mathematical talent.

No. Practical intelligence testing only began with the Binet scales between 1905 and 1916, and there is no record connecting Ramanujan to any test before his death in 1920 at age 32. Any IQ attached to his name was made up after the fact.

He was almost entirely self-taught. As a schoolboy he worked through Carr's Synopsis of elementary results in pure mathematics and then developed his own ideas in isolation, writing to Hardy in 1913: "I have had no university education but I have undergone the ordinary school course."

When Hardy visited Ramanujan in hospital he mentioned arriving in taxi number 1729, calling it dull. Ramanujan replied instantly that it is the smallest number expressible as the sum of two cubes in two different ways. The story comes from Hardy's own 1940 book.

He fell seriously ill in England, returned to India in 1919, and died on 26 April 1920 in Kumbakonam at age 32. His diagnosis was recorded at the time as tuberculosis, and later authors have debated the exact cause.

There is no measurement that can answer that; neither man has a verified IQ score. Within mathematics, Hardy's famous private rating gave Ramanujan 100 out of 100 for raw talent, with David Hilbert at 80 and Hardy himself at 25, which says how his peers saw him.

Ramanujan's story needs no invented number. A clerk with no degree taught himself mathematics from one borrowed book and ended his short life as a Fellow of the Royal Society, rated a perfect 100 by the era's sharpest judge of mathematical talent. Ramanujan can never be tested. You can be: the free RIOT IQ test, the Reasoning and Intelligence Online Test, reports a professionally normed score on the modern scale, which is the only kind of IQ number worth quoting.

1. O'Connor, J. J., & Robertson, E. F. (1998). Srinivasa Aiyangar Ramanujan. MacTutor History of Mathematics Archive, University of St Andrews. mathshistory.st-andrews.ac.uk

2. Berndt, B. C., Ono, K., & Alladi, K. (Eds.). (2012). Srinivasa Ramanujan: Going strong at 125, Part I. Notices of the American Mathematical Society, 59(11), 1522-1537. ams.org

3. Hardy, G. H. (1940). Ramanujan: Twelve lectures on subjects suggested by his life and work. Cambridge University Press. Key quotes collected at en.wikiquote.org

4. Terman, L. M. (1916). The measurement of intelligence. Houghton Mifflin. archive.org

5. Canivez, G. L. (2010). Review of the Wechsler Adult Intelligence Scale, Fourth Edition. In The eighteenth mental measurements yearbook. Buros Institute. ux1.eiu.edu