US Presidents Ranked by IQ: The Estimated Scores

How Simonton Actually Calculated the Numbers

Since he couldn't administer a test to James Madison or Andrew Jackson, Simonton used historiometry — applying quantitative methods to historical records. In plain terms, he scored each president on measurable proxies for intelligence and then converted those into an IQ-like figure.

The main ingredients were:

1. Openness to experience — curiosity, range of interests, and intellectual engagement, rated from documented behavior and writings.
2. Intellectual brilliance — a composite drawn from expert historians' assessments of each president's ideas, verbal skill, and reasoning.
3. Biographical evidence — education, authored works, early achievements, and other markers of cognitive ability after age 18.

He then used statistical modeling to translate these ratings into estimated IQ scores. It's a legitimate research technique with a long pedigree, going back to Catharine Cox's 1926 study that estimated the intelligence of 301 historical geniuses the same way. Simonton's broader point wasn't a trivia ranking at all: he found that raw brainpower only weakly predicted who became a great president, and that other traits mattered more.

Why You Should Treat These Estimates With Caution

The estimates are scholarship, but they are not measurements, and the gap matters. A few honest limits worth keeping in mind:

• No president ever took the test. Every number is inferred. The margin of error on a single historical estimate is large — Simonton himself framed these as approximations, not precise scores.
• The method rewards the well-documented. Presidents who wrote books, held degrees, or left rich paper trails (Jefferson, Wilson, Kennedy) score higher partly because there's more evidence of "brilliance" to rate. Grant, a plain-spoken general, had less of that record — which doesn't mean he was genuinely less intelligent.
• The scores may run high across the board. When your lowest estimate is 130, the scale is arguably compressed at the top. These figures are best read as a relative ranking among presidents, not as literal population IQs.
• Decimals imply false precision. A figure like "159.8" looks exact, but it's the output of a model averaging subjective historian ratings. Don't mistake the decimal point for accuracy.

In short: interesting, defensible, and worth reading — but not the same thing as a WAIS score.

The Fake Chart to Ignore

If you've seen a viral list claiming Bill Clinton had an IQ of 182 and another president scored 91, delete it from memory. That chart came from a 2001 hoax email attributed to the "Lovenstein Institute" — an organization that does not exist. The Associated Press debunked it, and outlets that ran it (including The Guardian) issued retractions. The fabricated numbers, ranking presidents by party in a suspiciously tidy pattern, were never based on any recognized method.

For contrast, Simonton's real study estimated George W. Bush's IQ at roughly 125–138 depending on the measure — nowhere near the hoax's "91." Whatever your politics, the fake chart tells you nothing; the peer-reviewed study is the only serious data point, and even it comes with the caveats above.

FAQ

Q: Who is the smartest US president by IQ?

A: John Quincy Adams, by Simonton's 2006 estimate (~175). Thomas Jefferson (~160) and John F. Kennedy (~159.8) follow closely. Remember these are historiometric estimates from biographical data, not scores from an actual IQ test.

Q: Did any president really take an IQ test?

A: No — not one whose result is public. Standardized IQ tests didn't exist for most of American history, and modern presidents have never released such scores. Every "presidential IQ" figure in circulation is an estimate or, in some cases, an outright hoax.

Q: Which president had the lowest estimated IQ?

A: Ulysses S. Grant, at about 130 in Simonton's study — still in the top ~2% of the general population. The compressed range is one reason to read these numbers as a relative ranking rather than literal measurements.

Q: Is the viral chart with Bush at 91 and Clinton at 182 real?

A: No, it's a well-documented 2001 hoax. It was credited to the nonexistent "Lovenstein Institute" and debunked by the Associated Press. Simonton's genuine study estimated far different figures for the same presidents.

References

• Simonton, D. K. (2006). Presidential IQ, Openness, Intellectual Brilliance, and Leadership: Estimates and Correlations for 42 U.S. Chief Executives. Political Psychology, 27(4), 511–526. Paper (PDF)
• Simonton, D. K. (2018). Intellectual Brilliance and Presidential Performance. PMC / National Library of Medicine. Article
• Wikipedia. U.S. presidential IQ hoax. Overview of the 2001 Lovenstein Institute hoax

Last updated: July 13, 2026