Trump, a Republican who will return to the White House on January 20, beat Vice President Kamala Harris, the Democratic nominee, last year and repeatedly called for the prosecution of his perceived enemies.
"... I would have beaten Trump, could have beaten Trump, and ... Kamala could have beaten Trump," Biden told reporters at the White House when asked if he regretted his initial decision to run for re-election.
Biden, 82, stepped aside after a disastrous debate against Trump, 78, sparked worries within the Democratic party that he could not win in November or serve out a second term.
"I thought it was important to unify the party," Biden said about his decision, adding it was the honour of his life to be president but he did not want to cause a party that was not unified to lose an election.
Regarding pardons, Biden suggested he was taking into account what Trump was saying about his intentions for retribution.
"The idea that he would punish people ... is outrageous," Biden said.
"There's still consideration ... but no decision."
Asked whether he was considering a pre-emptive pardon for himself, Biden said no. "I didn't do anything wrong."
Biden rarely held news conferences during his four years in the White House but took several questions from reporters on Friday.
He said new sanctions imposed on Russian oil could raise petrol prices by three or four cents per gallon but would have a profound effect on Russia's economy.
Biden, who cancelled a trip to Italy to stay in Washington to oversee the federal response to the fires in California, said he was disappointed that he would not be able to visit Pope Francis at the Vatican, but said it was more important for him to remain in town.
