The presidency requires intelligence, compassion and wisdom. To learn which presidents were the smartest, read this list of U.S. presidents ranked by IQ score.
Please note: It's important to note that the IQ scores mentioned in the table are estimations and not official IQ scores. These estimations have been made based on available data, historical records and other factors such as education, achievements, and personality traits of the presidents. IQ scores can only be measured accurately through standardized tests, and there is no official record of the IQ scores of most U.S. presidents.
45. Ulysses S. Grant, ESTIMATED IQ: 120
During his presidency, Ulysses S. Grant unified a divided nation and created economic stability. He oversaw the implementation of the 15th Amendment, which granted African Americans the right to vote. Although he never took an IQ test, his score is estimated to be 120.
44. Warren G. Harding, ESTIMATED IQ: 124
Warren G. Harding’s presidency is often remembered for numerous scandals. Although he had only an average IQ score, he achieved a number of important successes. Harding was a popular president, and his intelligence and charisma helped him to win the election in 1920.
43. Andrew Johnson, ESTIMATED IQ: 125
Andrew Johnson was the 17th president and was known for his intelligence and accomplishments. He had a successful presidency, despite his lack of formal education. His most notable achievement was the passage of the Reconstruction Acts of 1867.
42. Calvin Coolidge, ESTIMATED IQ: 127
41. William Howard Taft, ESTIMATED IQ: 126
William Howard Taft graduated from Yale University, was admitted to the Ohio bar and served as a judge on the Ohio Superior Court. Taft helped establish the Department of Labor during his presidency.
40. Harry S. Truman, ESTIMATED IQ: 128
Harry S. Truman was a shrewd leader who understood the importance of foreign policy and worked to strengthen America's standing in the world. Truman is remembered for supporting the Marshall Plan, the North Atlantic Treaty Organization and the United Nations.
39. Zachary Taylor, ESTIMATED IQ: 129
Despite not having any prior political experience, Zachary Taylor was a highly intelligent leader and made numerous achievements during his presidency. He worked tirelessly to resolve differences between the North and South.
38. James Buchanan Jr., ESTIMATED IQ: 129
During his presidency, James Buchanan successfully negotiated a settlement to the Utah War and was able to maintain the Union during the heated secession crisis. He established the first transcontinental railroad and signed the Homestead Act.
37. Ronald Reagan, ESTIMATED IQ: 130
Ronald Reagan’s presidency is remembered for ushering in a new era of economic prosperity and ending the Cold War. During his two terms in office, Ronald Reagan was able to pass several major pieces of legislation.
36. William McKinley, ESTIMATED IQ: 130
William McKinley was successful in passing the Dingley Tariff Act, which increased tariffs on imports, and the Gold Standard Act, which established the gold standard for U.S. currency.
35. Herbert Clark Hoover, ESTIMATED IQ: 130
Herbert Hoover was well known for his ability to solve complex problems. During his presidency, he successfully passed the Smoot-Hawley Tariff Act, which raised tariffs on foreign imports, and the Revenue Act of 1932.
34. James K. Polk, ESTIMATED IQ: 130.2
During his presidency, James K. Polk achieved the annexation of Texas, the settlement of the Oregon boundary dispute and the passage of the Walker Tariff. His intelligence, ambition and determination made him one of the most effective presidents in history. With an IQ of 130, he would have been eligible to join Mensa.
33. Richard Milhous Nixon, ESTIMATED IQ: 132
Richard Nixon was the first president to visit China, which opened the door for better U.S.-China relations. He negotiated a strategic arms limitation treaty with the USSR, leading to the end of the Vietnam War.
32. Dwight David Eisenhower, ESTIMATED IQ: 132
During his two terms as president, Dwight Eisenhower implemented the interstate highway system, championed civil rights and worked to reduce international tensions during the Cold War.
31. William Henry Harrison, ESTIMATED IQ: 132
William Harrison is remembered for his brief presidency, which lasted only 31 days, the shortest in American history. Despite his short tenure, he was able to sign the Preemption Act of 1841, which protected settlers' rights to purchase land, and appoint the first Postmaster General.
30. Martin Van Buren, ESTIMATED IQ: 133
Martin Van Buren’s major achievements include the establishment of the U.S. Treasury, the negotiation of the Webster-Ashburton Treaty and the passage of the Tariff of 1842. He also played a major role in the creation of the Democratic Party.
29. John Tyler, ESTIMATED IQ: 136.2
John Tyler was a strong advocate for states' rights and a committed unionist. During his presidency, he worked to reduce the national debt and expand commerce with foreign nations. He was a major advocate of the annexation of Texas.
28. James Monroe, ESTIMATED IQ: 139
During his presidency, James Monroe established a foreign policy of peace and neutrality, which he called the "Monroe Doctrine." While he might not have known where to take an IQ test, his score is reputed to be quite high at 139.
27. George Walker Bush, ESTIMATED IQ: 139
George W. Bush was an intelligent president who achieved many great things during his time in office. His major achievements include tax cuts, the No Child Left Behind Act and the establishment of the Department of Homeland Security.
26. Gerald Rudolph Ford Jr., ESTIMATED IQ: 140
During his brief presidency, Gerald Ford oversaw the end of the Vietnam War, proposed the Helsinki Accords and signed the Panama Canal treaties. He created the Department of Energy and the Environmental Protection Agency.
25. Joseph Robinette Biden Jr., ESTIMATED IQ: 140
Since taking office, Joe Biden has achieved several successes, including passing the American Rescue Plan and signing an executive order mandating masks for federal properties. He has made major strides in foreign policy, such as negotiating the Abraham Accords.
24. George Washington, ESTIMATED IQ: 140
During his presidency, George Washington successfully brought the young nation together after a fractious Revolutionary War. He was instrumental in the establishment of the U.S. Constitution and Bill of Rights.
23. Lyndon Baines Johnson, ESTIMATED IQ: 140
During his presidency, Lyndon Johnson helped pass the Civil Rights Act, Medicare and the Immigration and Nationality Act. He was instrumental in passing the Voting Rights Act and establishing the National Endowment for the Arts.
22. Abraham Lincoln, ESTIMATED IQ: 140
During his presidency, Abraham Lincoln successfully led America through the Civil War and abolished slavery. He was a brilliant leader and was successful in preserving the newly formed Union. Today, Lincoln is legendary for his wisdom and thoughtfulness in decision making.
21. James A. Garfield, ESTIMATED IQ: 141.5
During his short-lived presidency, James A. Garfield made a number of important accomplishments, such as signing the Pendleton Civil Service Act and supporting a tariff reduction. He worked to strengthen the nation's Navy, making it one of the most powerful in the world.
20. Chester Alan Arthur, ESTIMATED IQ: 142
Chester Alan Arthur was known for his intelligence and shrewdness. He was a tireless advocate for civil service reform, signing the Pendleton Civil Service Reform Act into law.
19. George Herbert Walker Bush, ESTIMATED IQ: 143
George H. W. Bush oversaw the fall of the Soviet Union, the end of the Cold War and the reunification of Germany. He pushed for greater economic growth and initiated a number of environmental initiatives.
18. Theodore Roosevelt, ESTIMATED IQ: 143
Theodore Roosevelt was instrumental in creating the United States Forest Service, establishing the first National Park and implementing the Meat Inspection Act. His intelligence was evident in the way he navigated difficult political waters.
17. Stephen Grover Cleveland, ESTIMATED IQ: 144
Grover Cleveland was the only president to serve two non-consecutive terms. During his presidency, he was responsible for major changes to the civil service system, including merit-based hiring and the Pendleton Civil Service Reform Act.
16. Donald John Trump, ESTIMATED IQ: 145
Donald Trump achieved several successes while in office, including passing the Tax Cuts and Jobs Act, repealing the individual mandate and making numerous economic reforms. Despite his controversial approach to the office, Trump's intelligence is evident.
15. Andrew Jackson, ESTIMATED IQ: 145
Andrew Jackson is remembered for being a leader of the common people. His presidency oversaw the forced relocation of Native American tribes and the establishment of the now-defunct Bank of the United States.
14. Benjamin Harrison, ESTIMATED IQ: 145
During his presidency, Benjamin Harrison passed the Sherman Antitrust Act and the McKinley Tariff Act. He established several national parks and helped expand the U.S. Navy. Harrison was a highly intelligent and well-educated man.
13. Woodrow Wilson, ESTIMATED IQ: 145
Woodrow Wilson was a noted scholar and philosopher. During his presidency, Wilson secured a lasting peace at the end of World War I and created the League of Nations. He championed the passage of the Federal Reserve Act and the Clayton Antitrust Act.
12. Rutherford Birchard Hayes, ESTIMATED IQ: 146
Rutherford B. Hayes is remembered as one of the most intelligent and capable presidents in U.S. history. His intelligence was evident in his establishment of the first civil service system and passing of the Compromise of 1877.
11. Franklin Pierce, ESTIMATED IQ: 147
Franklin Pierce achieved successes in foreign policy, most notably the Gadsden Purchase. Throughout his presidency, he successfully maintained a cordial relationship with Great Britain. He was a strong advocate for the expansion of slavery.
10. Millard Fillmore, ESTIMATED IQ: 149
Millard Fillmore is remembered for the Compromise of 1850, which attempted to resolve the dispute between the North and the South over slavery. Fillmore's keen understanding of the political landscape of his time helped him make decisions that benefited the country as a whole.
9. Franklin Delano Roosevelt, ESTIMATED IQ: 150
Franklin Roosevelt is renowned for leading the U.S. through the Great Depression and World War II. He also established the New Deal and the Social Security Act, which changed the country forever. His intelligence was evident in his ability to guide citizens through difficult times.
8. Barack Hussein Obama, ESTIMATED IQ: 155
Barack Obama’s intelligence is evident in his major achievements, including healthcare reform and the Paris Agreement. He engaged in meaningful dialogue with many world leaders. Obama is fondly remembered as one of the top celebrities with a high IQ.
7. John Adams Jr., ESTIMATED IQ: 155
John Adams was one of the original authors of the Declaration of Independence. He was one of the first to recognize the importance of the separation of powers and the need for checks and balances. His diplomatic efforts helped broker the Treaty of Paris.
6. James Madison Jr., ESTIMATED IQ: 155
James Madison is one of the nation’s Founding Fathers and main architects of the Constitution. During his presidency, Madison successfully led the country through the War of 1812.
5. James Earl Carter Jr., ESTIMATED IQ: 156
During his brief tenure, Jimmy Carter signed the Camp David Accords, which led to peace between Egypt and Israel. He initiated negotiations between the U.S. and China and established the Department of Energy.
4. William Jefferson Clinton, ESTIMATED IQ: 159
During his two-term presidency, Bill Clinton achieved successes in economic growth, foreign policy and welfare reform. His intelligence helped him create effective bi-partisan policies and develop a strong economy.
3. John Fitzgerald Kennedy, ESTIMATED IQ: 160
Although he was president for only three years, John F. Kennedy made many accomplishments, including the establishment of the Peace Corps, the successful resolution of the Cuban Missile Crisis and the implementation of the first major tax cuts since World War II.
2. Thomas Jefferson, ESTIMATED IQ: 160
Thomas Jefferson was the primary author of the Declaration of Independence, a major advocate of states’ rights and a major architect of the Louisiana Purchase. During his presidency, Jefferson was an advocate of civil liberties and a strong federal government.
1. John Quincy Adams, ESTIMATED IQ: 175
John Quincy Adams was the most intelligent president to have held office. He was a Harvard-educated lawyer, diplomat and experienced statesman. During his presidency, Adams established the National Road and passed the Tariff of 1828.