The Washington Post had an interesting article about Trump’s IQ:

Trump is not shy about his intellectual prowess. As he tweeted in 2013: “Sorry losers and haters, but my I.Q. is one of the highest -and you all know it! Please don’t feel so stupid or insecure, it’s not your fault.”

Of course, “smart” is a bit subjective. There’s book smarts as well as street smarts. Many would say Trump has run a pretty smart campaign. But clearly he’s saying that his brain is very sharp — as he puts it, “super-genius stuff.’’ At one point, Trump rebutted criticism from columnist George Will and GOP consultant Karl Rove by saying: “I’m much smarter than them. I think I have a much higher IQ. I think I went to a better college — better everything.”

Trump’s college background, in fact, is often his key piece of evidence for his intellectual superiority. But there’s less here than meets the eye. Trump did graduate from the Wharton School of business at the University of Pennsylvania, an Ivy League college. But Trump did not get an MBA from Wharton; he has a much less prestigious undergraduate degree. He was a transfer student who arrived at Wharton after two years at Fordham University, which U.S. News & World Report currently ranks 66th among national universities. (Besides, simply going to an Ivy League school doesn’t prove you’re a genius.)

Gwenda Blair, in her 2001 book “The Trumps,” said that Trump’s grades at Fordham were just “respectable” and that he got into Wharton mainly because he had an interview with an admissions officer who had been a high school classmate of his older brother. And Wharton’s admissions team surely knew that Trump was from one of New York’s wealthiest families.

The average SAT score at Fordham University (reading + math) is 1260 (post-1995 scale).  This equates to an IQ of about 123 (white norms) and there’s no reason to think it’d be much different in Trump’s day.  But since Fordham students are selected by SAT scores, we’d expect them to regress to the U.S. mean (about 98 in Trump’s day) on an IQ test for which they were not selected.

I estimate that in the general U.S. population, the SAT correlates between 0.53 and  0.74 with the WAIS IQ test, so Fordham students who were 25 points above the U.S. mean of 98, would regress to anywhere from 53% to 74% of 25 points above 98, so either a mean IQ of 113 to 117.

The fact that Trump had “respectable grades” suggests he was as least as smart as the average Fordham student, but perhaps not much smarter, so IQ 113 to 117.
On the other hand, Trump’s failure to multiply 17 by 6, implies an IQ of only 94.
 But if Trump can hold his own in the debate against Hillary that starts in less than an hour, then I may have gravely underestimated him.  For national merit finalist Hillary has an IQ of at least 140 as measured by the PSAT (though probably no higher than 140 since she flunked the bar exam).
 If Trump’s IQ is indeed only 94, this will be the greatest IQ mismatch in the history of presidential debates, and Trump is at risk for massive humiliation.  However if his IQ is 113 to 117, as his grades suggest, then he might do fine.  JFK (IQ 119) more than held his own against Nixon (IQ 143), and Reagan more than held his own against Carter despite perhaps an even bigger IQ gap.