Age of U.S. presidents
Age of presidents when assuming office approximately follows a bell curve
(mean age marked by red line, c. 55.5 years)
The median age upon accession to the presidency is 55 years and 3 months. This is how old Lyndon B. Johnson was at the time of his inauguration. The youngest person to assume the office was Theodore Roosevelt, who became president at the age of 42 years, 322 days, following William McKinley's assassination; the oldest was Donald Trump, who was 70 years, 220 days old at his inauguration. The youngest person to be elected president was John F. Kennedy, at 43 years, 163 days of age on election day; the oldest was Ronald Reagan, who was 73 years, 274 days old at the time of his election to a second term.
Assassinated three years into his term, John F. Kennedy was the youngest at the time of leaving office (46 years, 177 days); the youngest president to leave office at the conclusion of a normal transition was Theodore Roosevelt (50 years, 128 days). The oldest at the time of leaving office was Ronald Reagan (77 years, 349 days).
Born on May 29, 1917, John F. Kennedy was younger than four of his successors, the greatest number to date: Lyndon Johnson (8 years, 9 months, and 2 days); Ronald Reagan (6 years, 3 months, and 23 days); Richard Nixon (4 years, 4 months, and 16 days); and Gerald Ford (3 years, 10 months, and 15 days).
Born on February 6, 1911, Ronald Reagan was older than four of his predecessors, the greatest number to date: Richard Nixon (1 year, 11 months, and 7 days); Gerald Ford (2 years, 5 months, and 8 days); John F. Kennedy (6 years, 3 months, and 23 days); and Jimmy Carter (13 years, 7 months, and 25 days).
Three presidents—Donald Trump, George W. Bush, and Bill Clinton—were born in 1946 (all within the span of 9 weeks). This is the only calendar year in which three presidents have been born. Two presidents—James K. Polk and Warren G. Harding—were born on November 2 (70 years apart). This is the only day of the year having the birthday of multiple presidents.
The oldest living U.S. president is George H. W. Bush, born June 12, 1924 (age 94 years, 34 days). On November 25, 2017, he also became the longest-lived president, surpassing the lifespan of Gerald Ford, who died at the age of 93 years, 165 days. The second oldest living president, Jimmy Carter, has the distinction of having the longest post-presidency in U.S. history, currently at 37 years, 177 days. He surpassed the previous record, held by Herbert Hoover (31 years, 230 days) on September 7, 2012. The youngest living president is Barack Obama, born August 4, 1961 (age 56 years, 346 days).
The shortest-lived president to have died by natural causes (thereby excluding John F. Kennedy and James A. Garfield, who were both assassinated) was James K. Polk, who died of cholera at the age of 53 years, 225 days; only 103 days after leaving office.
Six U.S. presidents have lived into their 90s, with two of them currently alive. They are (in order of birth):
George H. W. Bush