Presidential Age Entering and Leaving Office

The Constitution of the United States has very few requirements for becoming President of the United States. One of those simple requirements is that you have to be at least 35 years old.

The Constitution: Article 2, Section 1, Clause 5

“No Person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President; neither shall any Person be eligible to that Office who shall not have attained to the Age of thirty five Years, and been fourteen Years a Resident within the United States.”

So, who are the youngest and oldest Presidents to enter the White House? Who were the youngest and oldest to leave the White House? What is the average age of a President entering or leaving the White House?

Top 10 Youngest Presidents Entering Office

                                   Age Entering Office
       President                Year       Days
Theodore Roosevelt         42           322
John “JFK” Kennedy         43           236
Bill Clinton                         46           154
Ulysses S. Grant               46           311
Barack Obama                  47           169
Grover Cleveland              47           351
Franklin Pierce                  48           101
James Garfield                  49           105
James K. Polk                   49           122
Millard Fillmore                  50           183

Top 10 Oldest Presidents Entering Office

                                   Age Entering Office
       President                    Year   Days
Donald Trump                       70      220
Ronald Reagan                     69      349
William Henry Harrison          68      23
James Buchanan                   65     315
George HW Bush                   64     222
Zachary Taylor                       64     100
Dwight Eisenhower                62       98
Andrew Jackson                     61     354
John Adams                           61      125
Gerald Ford                            61       26

Top 10 Youngest Presidents Leaving Office

                                   Age Leaving Office
       President                  Year    Days
John “JFK” Kennedy          46        177
James Garfield                   49        304
Theodore Roosevelt           50       128
Grover Cleveland               51        351
Franklin Pierce                   52        101
Millard Fillmore                   53         56
James K. Polk                    53        122
Bill Clinton                          54        154
Ulysses S. Grant                54        311
John Tyler                          54        340

Top 10 Oldest Presidents Leaving Office

                                            Age Leaving Office
          President                       Year     Days
Ronald Reagan                           77         49
Dwight Eisenhower                     70          98
Andrew Jackson                          69        354
James Buchanan                         69        315
Harry S Truman                           68        257
George HW Bush                        68         222
William Henry Harrison                68         54
James Monroe                             66        310
James Madison                            65        353
Thomas Jefferson                        65        325

Side notes: The “average” age for a President to enter his term is 55 years, 174.5 days. The closest President to that average is Benjamin Harrison (55 years, 196 days when he entered his term). The “average” age for a President to leave office is 60 years, 115 days. Lyndon Johnson (60 years, 146 days when he left office) is the closet President to that “average.” Donald Trump will be, at the very least, the second oldest President to leave office. He currently holds that title, but would need to be re-elected and serve most of that second term to claim the title of the oldest President to leave office.