Bill Gates reportedly scored 1590 on the SAT in the early 1970s (Verbal 790 + Math 800). In a rare study done in 1974, it was estimated that if all American teens took the SAT that year (instead of just the college bound elite) , the verbal mean would be 368 (SD 111) and the math would be 402 (SD 112). Assuming a 0.67 correlation between the two subscales, a combined mean of 770 (SD 203.8) is implied.

Thus Gates’s scores equated to a verbal IQ of 157, a math IQ of 153+, and a combined IQ of 160.

However these numbers assume the SAT was normally distributed, and yet empirical data from the 1980s suggests near perfect scores were much more rare than the normal curve predicts and equated to an IQ of about 170 and if anything they were likely even more rare in the 1970s when fewer people studied for the SAT.

Another reason why these numbers likely underestimate Gates’s IQ is that he hit the ceiling on the math section.

Thus I found the following part of a 2001 article in Time magazine of interest:

“In ninth grade,” Gates recalls over dinner one night, “I came up with a new form of rebellion. I hadn’t been getting good grades, but I decided to get all A’s without taking a book home. I didn’t go to math class, because I knew enough and had read ahead, and I placed within the top 10 people in the nation on an aptitude exam. That established my independence and taught me I didn’t need to rebel anymore.” By 10th grade he was teaching computers and writing a program that handled class scheduling, which had a secret function that placed him in classes with the right girls.

According to this source, there were 4,097,000 Americans born the same year Gates was.  Some of them would have died before reaching the ninth grade, but these probably would have been made up for by immigrants, so Gates being in the top ten in the nation for his age or grade level, implies he scored in the top one in 409,700.  This equates to a math IQ of 168.

In other words, had the SAT had a higher ceiling in the 1970s, he would have perhaps scored 910 (the equivalent of IQ 168). Add this to his verbal score of 790, and we get a combined score of 1700, which would have equated to a combined IQ of about 170. So even if we assume 1970s SAT scores were normally distributed, Gates still clocks in at IQ 170 as long as we extend the ceiling.

Commenter Bruno has expressed considerable skepticism about Gates having an IQ this high, citing the fact that he was not the top math student at Harvard.

My response is that a) standardized test scores should be given more weight than school grades, and b) Gates spent his teens obsessing over computers so math IQ made him the best programmer at Harvard instead of the best math student per se. The title of best math student probably went to an equally smart person who spent their teens obsessing over math.

The video clips are from the fascinating new Netflix series Inside Bill’s Brain.

It seems Gates has really mellowed out in recent decades, or at least become better at hiding his arrogance. In the below clip you can see him berating his employees and making a bizarre head twirling facial expression as if implying the employee is mentally retarded.

Indeed with an IQ of 170, even the average member of America’s political, economic, and cultural elite (IQ 125 to 135) is literally mentally retarded compared to Gates, which helps explain how he was able to leapfrog over the establishment to become the richest man of the 20th century, with such a stranglehold over the market that it took the U.S. justice department to stop his complete domination.