William James Sidis

One of the smartest men and highest IQ.

James William Sidis

William James Sidis was a child prodigy in America who lived from April 1, 1898 to July 17, 1944. He had precocious abilities in math and linguistics, while publishing several books under many pseudonyms. It is said that most genius’ who have lived were born ahead of their time, but in the case of Billy Sidis, he seems to have been born in the wrong time completely. He was born to Boris and Sarah Sidis in New York City. His mother graduated from Boston University’s School of Medicine while Boris graduated from Harvard University with several degrees. Boris himself was a distinguished genius, a famous psychiatrist who published several books and articles, and a polyglot or multi-linguist. The following article includes many of the capabilities and accomplishments of William Sidis.

His First Year

William accomplished many things out of the ordinary that helped show his potential in his first year of life. He listened to Greek myths as bedtime stories from his mother. He started feeding himself at eight months with a spoon and learned the alphabet from blocks hanging in his crib. He said the word “door” at six months and told his mother a couple months later that he liked doors, things, and people that move. At seven months he pointed to the moon and said he “wanted a moon of his own.” And by the time he turned one, he was able to spell a plethora of impressive vocabulary words.

Learning Abilities

As he grew and matured, Sidis proved capable in everything he tried. He was able to read entire issues of the New York Times at 18 months. At three he used his high chair to reach the family typewriter and taught himself how to use it and even composed a letter to Macy’s requesting new toys form their store. At the age of six he learned Aristotelian logic and became an extreme atheist after studying all of the religions. But the most fascinating skill he had was total recall of everything he read, otherwise known as a photographic memory.

Linguistic Capabilities

He showed prodigal tendencies in Linguistics ever since he was a child. He learned the Greek alphabet and read Homer in Greek at the age of four. He also read Caesar’s Gallic Wars in Latin, which he self-taught, as a birthday present to his farther in his fourth year. When he was six, Sidis learned Russian, French, German, Hebrew, Turkish, and Armenian. He also invented a language called Vendergood and could learn a whole language in a single day. By the time he passed away, he knew all the languages, around 200 of them, of the world and could translate among them instantly.

Mathematical Prowess

Like his skills in linguistics, he was precocious in math. For instance, he created a logarithm in his sixth year to calculate the day of the week on any day in history. He also corrected E. V. Huntington’s mathematics text galleys at the age of eight. He surpassed his father, who was also a genius, in mathematics at the age of eight and mastered higher mathematics and planetary revolutions at age 11. He also lectured Harvard Mathematical Club on Four-Dimensional Bodies when he was 11. After the lecture on Four-Dimensional Bodies, Professor Daniel Comstock of MIT told reporters that William Sidis would someday be the greatest mathematician of the century.

Writing and Passing Tests

Sidis wrote four books between the age of four and eight, two on Anatomy and two on Astronomy. He read and learned Gray’s Anatomy by Henry Gray at age six, which would help him pass a student medical examination. And thus, he passed the Harvard Medical School Anatomy Exam at seven years old and then when he turned eight, passed the MIT Entrance Exam.


William Sidis started grammar school at age six, finished third grade in three days, and graduated grammar school in seven months. He was able to get into Harvard at nine, but was told to take a couple years off to allow his personality to catch up with his intellect. At the age of ten, in a single evening, corrected Harvard logic professor Josiah Royce’s book manuscript. He became the youngest student ever to enroll at Harvard at 11. Graduated from Harvard, cum laude, at the age of 16 and entered Harvard Law School in 1916.


To put his IQ in perspective, there are some numbers to realize first. The average IQ of society is 100, with an IQ above 140 giving people the title of a genius. Some of the famous genuis’ IQ in history include George Washington with 140, Mozart and Charles Darwin with 153, Benjamin Franklin and Albert Einstein with 160, Leonardo da Vinci at a 180, and Sir Isaac Newton with a whopping IQ of 190. William James Sidis, on the other hand, had an IQ estimated to be around 250–300! Although IQ plays only a small role in intelligence and doesn’t account for creativity or other important areas that combine to form genius, an IQ that high is still incredibly impressive.