Joe Biden and Donald Trump are the oldest presidents ever to take office in the United States.

While Biden was 78 in 2021 and remains a single-term president, Trump was 70 when he was inaugurated in 2017 and is 78 when he begins his second, non-consecutive term on Monday. Ronald Reagan, who was 69 in 1981, is third. Like Biden, Trump would be 82 when he finishes his term. Biden would be 86 at the end of a hypothetical second term.

A look at the ages of every president since 1789 at their inauguration reveals no clear trend.