As of March 21, 2019, Jimmy Carter is now the United States’ oldest living former president. Carter is now 94 years and 172 days old. George H.W. Bush was 94 years and 171 days old when he passed last November.

Not many presidents have lived into their 90s; our first leader, George Washington, only lived until 67 years old.

The average age of a person becoming president is 55 years and 3 months old. Carter was 52 years old when he became president.

Source: https://thehill.com/blogs/in-the-know/in-the-know/435079-jimmy-carter-becomes-oldest-living-president-in-history