In the first Republican debate, Ben Carson argued that when it comes to being a good president, “the thing that is probably most important is having a brain.”

While a high IQ does not guarantee success, it is true that intelligence is often associated with effective leaders. But does that trend hold true for U.S. presidents? Are the most successful presidents also the most intelligent?

With that question in mind, InsideGov ranked the 27 smartest presidents in U.S. history, using data from UC Davis professor, Dean Simonton.

In a 2006 study, Simonton used historiometric methods to estimate each president’s IQ, analyzing information from their biographies and writings that would indicate a higher-than-average intellect.

This list is by no means definitive, but it should give a good sense of which presidents were highly intellectual. Interestingly, eight of the presidents on this list either never attended college or dropped out before finishing their degrees.

Keep reading to discover presidents ranked by IQ.

Key Takeaways: 27 Smartest Presidents by IQ

  1. Intelligence and presidency: A study by UC Davis professor Dean Simonton estimates the IQs of U.S. presidents, suggesting a correlation between intelligence and effective leadership.
  2. Diverse educational backgrounds: Some of the most intellectual presidents did not complete college, challenging the conventional correlation between formal education and intelligence.
  3. Top intellects: Presidents like John Quincy Adams, Thomas Jefferson, and John F. Kennedy are highlighted for their high IQ scores and significant contributions to the country.
  4. Influence of intelligence on policy and leadership: The study implies that higher intelligence can impact presidential success and decision-making capabilities.
  5. Debate on criteria for ‘smartest’: The discussion continues on what measures—such as emotional intelligence, decision-making skills, and the ability to connect with people—define a truly successful president.

*Note: Simonton estimated four different IQ values for each president. We averaged all four IQs to get our ranking. President Obama was not included in the study.

#27. George H. W. Bush

IQ: 130.1
College: Yale University

Before he attended Yale, George H. W. Bush enlisted in the Navy and served until the end of World War II. He also had a successful career in the oil industry before turning to politics.

Presidency summary: Managed the end of the Cold War and led a successful military operation in the Gulf War.

#26. William McKinley

IQ: 130.2
College: Allegheny College (withdrew)

Although William McKinley dropped out of Allegheny College, he would later earn a law degree from Albany Law School. He also served in the Civil War and became a lawyer.

President McKinley was tragically assassinated just six months into his second term.

Presidency summary: Oversaw a period of economic growth and led the nation during the Spanish-American War.

#25. James K. Polk

IQ: 130.2
College: University of North Carolina at Chapel Hill

Polk has been called the “least known consequential president.” Before being elected, he was a lawyer and Speaker of the House.

In his one term as president, Polk presided over the Mexican War, dramatically expanded the size of the country, and overhauled the nation’s finance system.

Presidency summary: Achieved significant territorial expansion of the U.S., including the acquisition of California.

#24. Grover Cleveland

IQ: 130.9
College: None

Cleveland couldn’t afford a college education, but that didn’t stop him from becoming a successful lawyer. He rose from his humble beginnings and became a lawyer and mayor of Buffalo.

As president, Cleveland earned a reputation for his honesty and work ethic.

Presidency summary: Known for his fight against corruption and efforts to reform the civil service.

#23. Richard Nixon

IQ: 131.0
College: Whittier College

Before becoming president, Nixon served in the Navy during WWII and became a lawyer. Nixon may have had the most scandal-filled presidency, but there’s no doubting his intelligence.

Before he resigned from office, Nixon actually accomplished some major foreign policy goals and pushed for more environmental regulation.

Presidency summary: Opened diplomatic relations with China and initiated détente with the Soviet Union.

#22. Dwight D. Eisenhower

IQ: 131.9
College: U.S. Military Academy (West Point)

Before becoming president, Eisenhower served as a five-star general in the army during World War II and was the Supreme Commander of the Allied Forces in Europe. Eisenhower also served as the president of Columbia University from 1948 to 1953.

Presidency summary: Promoted Atoms for Peace and initiated the Interstate Highway System.

#21. Benjamin Harrison

IQ: 132.2
College: Miami University

Benjamin Harrison had a successful career as an attorney before and after his one-term presidency. He even represented the Republic of Venezuela against the United Kingdom.

Presidency summary: Known for his environmental conservation efforts and modernizing the Navy.

#20. George Washington

IQ: 132.5
College: None

Washington managed to become the first U.S. president without a college degree. In addition to having a sharp political mind, Washington was also a skilled military commander.

Presidency summary: He set many precedents for the role of President and kept the nation neutral during European conflicts.

#19. Martin Van Buren

IQ: 133.4
College: None

Van Buren began reading law at the age of 14 and was admitted to the bar just seven years later. Along with Andrew Jackson, he was one of the most influential architects of the original Democratic Party.

Presidency summary: He faced economic hardships but established an independent treasury system.

#18. Rutherford B. Hayes

IQ: 133.9
College: Kenyon College

Like his predecessor, Ulysses S. Grant, Hayes struggled to reconcile the country after the Civil War. He is generally regarded as an unexceptional president.

Presidency summary: He ended Reconstruction and promoted civil service reform.

#17. William Henry Harrison

IQ: 133.9
College: Hampden-Sydney College (withdrew)

Sadly, William Henry Harrison’s presidency ended just 32 days into his first term, when he died of pneumonia. Before his presidency, Harrison gained fame for his military career.

Presidency summary: Unfortunatley, he doesn’t have any significant achievements, except for holding the title of “the shortest presidency in U.S. history”.

#16. Franklin Pierce

IQ: 134.8
College: Bowdoin College

Not even a brilliant mind could save Pierce from a disastrous presidency. His failure to deal with the issue of slavery helped escalate the onset of the Civil War.

Presidency summary: His policies furthered the division leading to the Civil War.

#15. Millard Fillmore

IQ: 136.0
College: None

Like Pierce, Fillmore failed to adequately address the issue of slavery. Although he never attended college, he helped found the University at Buffalo.

Presidency summary: His Compromise of 1850 was a controversial attempt to avoid civil war.

#14. John Tyler

IQ: 136.2
College: College of William and Mary

Tyler has an impressive pre-presidency career, serving as a governor, U.S. representative and senator. However, he had a fairly unimpressive presidency.

Presidency summary: Annexed Texas but faced opposition for his policies.

#13. Franklin D. Roosevelt

IQ: 139.6
College: Harvard University

In terms of influence, few presidents can match FDR’s 12 years as president. Roosevelt was also one of the most intellectual presidents to occupy the White House.

Presidency summary: Led the U.S. through the Great Depression and most of WWII.

#12. Abraham Lincoln

IQ: 140
College: None

With an estimated IQ of 140, Lincoln is undoubtedly one of the smartest presidents. Despite never obtaining a college degree, Lincoln was a highly-respected lawyer and a skilled orator.

Presidency summary: Led the nation through the Civil War and abolished slavery.

#11. James Madison

IQ: 141.3
College: Princeton University

As the “Father of the Constitution” and one of the key architects of the Bill of Rights, James Madison was certainly one of the most intelligent and influential U.S. presidents.

Presidency summary: Led the nation during the War of 1812 and established the Second Bank of the U.S.

Now let’s move to the greatest of all – the top 10 most intelligent presidents in the world.

#10. Chester A. Arthur

IQ: 141.5
College: Union College

Despite being one of the most intelligent presidents, Chester A. Arthur is generally regarded as being an inconsequential leader.

Nonetheless, Arthur deserves credit for championing reform in a time of rampant political corruption.

Presidency summary: Known for the Pendleton Civil Service Reform Act.

#9. James Garfield

IQ: 141.5
College: Williams College

Garfield excelled as a student at Williams College, where he graduated second in his class. It was said that Garfield could write Latin with one hand and ancient Greek with the other.

Presidency summary: His term was cut short by assassination; he advocated for civil rights and education.

#8. Theodore Roosevelt

IQ: 142.3
College: Harvard University

Teddy Roosevelt was certainly one of the most intellectually curious presidents to occupy the White House.

A prolific author, he published 35 books on subjects ranging from the War of 1812 to African game trails. He was also a respected naturalist and conservationist.

Presidency summary: Known for his progressive policies, conservation efforts, and the Panama Canal.

#7. John Adams

IQ: 142.5
College: Harvard University

Adams was a highly intellectual political theorist, historian, lawyer and politician. Growing up, he excelled in Latin school and was admitted to Harvard College at the young age of 15.

Presidency summary: Played a key role in the founding of the U.S. and faced challenges with France.

#6. Jimmy Carter

IQ: 145.1
College: U.S. Naval Academy

Jimmy Carter is a case where a high IQ didn’t necessarily equate to a successful presidency.

Before becoming president, Carter graduated with a bachelor of science degree from the Naval Academy and later took graduate courses on nuclear physics at Union College.

Presidency summary: Focused on human rights; brokered the Camp David Accords.

#5. Woodrow Wilson

IQ: 145.1
College: Princeton University

Wilson earned a Ph.D. in political science and was chosen to be president of Princeton University, a position he held from 1902 to 1910.

As president, Wilson was a key figure in the Progressive Movement and presided over World War I.

Presidency summary: Led the U.S. during WWI and was a key figure in establishing the League of Nations.

#4. Bill Clinton

IQ: 148.8
College: Georgetown University

Clinton was elected to Phi Beta Kappa at Georgetown University and won a Rhodes Scholarship to Oxford University, where he studied philosophy, politics and economics.

He also received a law degree from Yale.

Presidency summary: Oversaw a period of economic prosperity and implemented welfare reform.

#3. John F. Kennedy

IQ: 150.7
College: Harvard University

At 43, Kennedy was the youngest person to be elected president. Although he frequently struggled with health issues, Kennedy was nonetheless an avid scholar and an ambitious statesman.

Presidency summary: Known for the Cuban Missile Crisis management and initiating the space race.

#2. Thomas Jefferson

IQ: 153.8
College: College of William and Mary (withdrew)

When speaking at a White House dinner for Nobel Laureates, JFK famously noted, “I think this is the most extraordinary collection of talent, of human knowledge, that has ever been gathered together at the White House, with the possible exception of when Thomas Jefferson dined alone.”

Jefferson certainly was a true Renaissance figure, studying everything from agricultural innovation to architecture.

Presidency summary: Doubled the size of the U.S. with the Louisiana Purchase; advocated for democracy and individual rights.

#1. John Quincy Adams – The Smartest President of All Time

IQ: 168.8
College: Harvard University

Like his father, John Quincy Adams was an esteemed lawyer and a formidable presence in court (he earned a law degree from Harvard). He was also a brilliant statesman, negotiating several key international treaties. Remarkably, Adams was fluent in at least four languages and regularly translated Latin and ancient Greek, as well.

Presidency summary: Focused on modernizing the economy and promoting education.

Final Thoughts

Exploring the smartest presidents of the U.S. reveals a fascinating intersection of intelligence, leadership, and policy-making.

While the definition of ‘smartest’ is subjective, based on criteria such as academic achievements, eloquence, problem-solving skills, or visionary policies, it is clear that intellectual strength has played a significant role in shaping the history and governance of the United States.

Presidents like Jefferson, Lincoln, and Roosevelt, among others, exemplify how diverse forms of intelligence have contributed to their impactful presidencies.

However, it is crucial to recognize that intelligence alone does not define a successful presidency.

Leadership qualities, emotional intelligence, decision-making abilities, and the capacity to connect with the populace are equally vital.

This exploration underscores the multifaceted nature of presidential success and the diverse forms of intelligence that have contributed to the legacy of these leaders.

Sources: Research U.S. Presidents on InsideGov

Read more: 25 Facts About Abraham Lincoln