At least among those whose life dates are certain.
Jorge Mario Bergoglio, born on 17 December 1936, will then be exactly 32,082 days old.
Only Leo XIII (Vincenzo Gioacchino Pecci), who died on 20 July 1903 at the blessed age of 34,108 days (93 years), was older.
To catch up with him, Francis would have to reign until 7 May 2030.
The second oldest pope in office to date was Clement XII, born in 1652. He died on 6 February 1740 after a lifetime of 32,081 days.
Benedict XVI (Joseph Ratzinger) was 31,122 days old when he stepped down as pope on 28 February 2013.
John Paul II was 31,001 days old; he died on 2 April 2005.