Even though it’s widely acknowledged that intelligence is more complex than a number, IQ tests can nonetheless provide insight into a person’s mental processes, particularly in situations where face-to-face communication is not feasible. It’s reasonable to question how historical personalities might have fared on the IQ test, and since the exam was developed in 1905, there are enough of historical figures on which to base one’s speculations. Allowing his curiosity to take over, University of California, Davis psychology professor Dean Simonton undertook a study in 2006 wherein he assigned IQ scores to every US president from George Washington to George W. Bush.

What grade do you believe the US presidents received? Continue reading to learn more.

Gerald Ford

The 38th president of the United States, Gerald Ford, scored 127.08 on the IQ scale. He not only attended Yale Law School and received his degree there, but he also worked as the team’s coach during his time there.

Calvin Coolidge

With an IQ of 127.1, the 30th president was fondly referred to as Silent Cal. Acknowledged for his unwavering support of equal rights, Coolidge also received awards from Amherst College in Massachusetts, where he was partly responsible for the Great Depression.

Harry Truman

Harry Truman, the 33rd president of the United States, never attended college despite having an IQ of 127.55. Truman found it challenging to follow along because he was actually blind in one eye, and he left college after just one year.

Lyndon B. Johnson

After John F. Kennedy was assassinated, Lyndon B. Johnson took over as the 36th president. With an IQ of 127.83, he was a lifelong studier. Johnson attended what is now Texas State University and finished with a teaching credential and a bachelor’s degree in history after winning the election to be his class’s president in the eleventh grade.

Herbert Hoover

As the thirty-first president during the Great Depression, Herbert Hoover was not especially well-liked, but he had a track record of achievement and hard work from an early age. Hoover, who studied geology at Stanford and had an IQ of 129.78, started his own side company doing other students’ laundry.

Ronald Reagan

The 40th president of the United States, Ronald Reagan, scored 130 on the IQ scale. Even though he was intelligent, Reagan didn’t care much for education and received a C average when he finished from college. Reagan then tried jobs in radio and movies, but politics eventually drew him in.

George H.W. Bush / William McKinley

Despite having identical IQs of 130.13, the 25th and 41st presidents’ educational backgrounds couldn’t have been more dissimilar. While Bush completed his studies in two and a half years, graduating Phi Betta Kappa from Yale University and holding the positions of captain of the baseball team and president of his fraternity, McKinley only attended one year of college before deciding to fight for the Union in the Civil War.

James K. Polk

The eleventh president of the United States, James K. Polk, had an IQ of 130.2 and appeared to utilize every point of it. Known as one of the most successful US presidents ever, Polk successfully fulfilled all of his campaign pledges to extend the US border to the Pacific Ocean.

Grover Cleveland

In American history, Grover Cleveland, the 22nd and 24th presidents, is the only person to have held the office for two terms that were not consecutive. Because of his personal financial constraints, he was also one of the few presidents to forgo attending college. Nonetheless, Cleveland became sufficiently self-taught in law—despite having no professional tutoring—to pass the bar exam because of his 130.95 IQ.

Richard Nixon

37th President Richard Nixon had been an almost perfect student before the Watergate affair ruined whatever chance he had to leave a good legacy. Nixon, whose IQ was 131, graduated with honors from Whittier University with a bachelor’s degree in history before being awarded a scholarship to Duke Law School. This was despite his family’s financial difficulties.

Dwight D. Eisenhower

Even with his high IQ of 131.9, Dwight D. Eisenhower was reportedly not very engaged in school when he was younger. The potential 34th president was a below-average student at West Point Military Academy who committed numerous disciplinary violations.

Benjamin Harrison

Even with his high IQ of 131.9, Dwight D. Eisenhower was reportedly not very engaged in school when he was younger. The potential 34th president was a below-average student at West Point Military Academy who committed numerous disciplinary violations.

George Washington

Despite being estimated to have an IQ of 132.5, the first president of the United States, George Washington, never completed elementary school. Still, at seventeen Washington was a surveyor; at twenty-three he was a military leader.

Martin Van Buren

Martin Van Buren stands out from all other presidents in history for being the only one to have studied English as a second language and the first who did not originate from an English-speaking family, even if he is not much remembered in current times. With an IQ of 133.35, the eighth president was born into a low-income Dutch family in New York.

Rutherford B. Hayes / William Henry Harrison

Rutherford Hayes and William Harrison, who together served as ten presidents, were believed to have had IQs of 133.93. The ninth president, Harrison, was only in office for thirty days after becoming very ill following his inauguration. The 19th president, Hayes, practiced law before taking office and was committed to upholding the rights of former slaves who had fled the Southern states.

Franklin Pierce

With an IQ of 134.78, Franklin Pierce was one of the poorest and most damaging presidents in history, but he was nonetheless regarded as such. Before becoming president, Pierce was an ordinary and unremarkable student. He pursued strong expansionist and anti-abolitionist policies, which sparked the Civil War.

Millard Fillmore

The thirteenth president of the United States, Millard Fillmore, was reported to have had an IQ of 135.98, which undoubtedly helped him along the road as a young man with little formal education. From these modest beginnings, Fillmore went on to become a lawyer and, in 1850, the president without a formal education.

John Tyler

The thirteenth president of the United States, Millard Fillmore, was reported to have had an IQ of 135.98, which undoubtedly helped him along the road as a young man with little formal education. From these modest beginnings, Fillmore went on to become a lawyer and, in 1850, the president without a formal education.

Franklin D. Roosevelt

It seems sense that the president with the highest IQ in contemporary history would also be one of the most powerful figures in the country. Roosevelt, who scored a 139.6 on the IQ test, went to Columbia Law School before becoming president, but he left after passing the New York Bar Exam.

Abraham Lincoln

Abraham Lincoln, one of the most well-known presidents in American history, was on the verge of being a genius with an estimated IQ of 140. Without going to college, Lincoln taught himself the law and went on to become a successful lawyer before becoming the famous president.

James Madison

With an IQ of 141.25, James Madison became the fourth president of the United States. He was a young, bright student at Princeton University, finishing his three-year degree in just two years. As a result of his involvement in several of the Constitution’s drafts, he was given the moniker “Father of the Constitution.”

James Garfield / Chester Arthur

Chester Arthur, the twenty-first president of the United States, and James Garfield, the twenty-first, both had IQs of 141.5. Both Garfield and Arthur experienced bullying as schoolboys: Garfield for lacking a father and Arthur for being overweight. However, both were also excellent students—Arthur was the president of his debate team, and Garfield placed second in his class.

Bill Clinton

With an IQ of 148.8, Bill Clinton is the only president to have been both a Rhodes Scholar and the 42nd president of the United States. Clinton’s inherent intelligence helped him secure a scholarship to Georgetown University in Virginia. He later attended Oxford University with a Rhodes Scholarship before enrolling at Yale Law School.

Thomas Jefferson

Undoubtedly, one of the busiest Americans in history was Thomas Jefferson. Jefferson, whose estimated IQ was 153.75, was not only the third president of the United States but also the founder of the University of Virginia, president of the American Philosophical Society, and the main author of the Declaration of Independence.

John Quincy Adams

John Quincy Adams, the sixth president of the United States, is believed to have had an extraordinarily high IQ score of 168.75, making him the president with the highest estimated IQ of all time by a significant margin. Thanks in great part to the influence of his father John Adams, Adams shown brilliance at a young age and was an enthusiastic reader and translator of classical Greek and Latin works. In addition, he is well-known for keeping a journal from his early years till his passing.