But he insisted such a decision would be a “mistake," as he spent his Thanksgiving renewing baseless claims that "massive fraud" and crooked officials caused his election defeat.
While there is no evidence of the kind of widespread fraud President Trump has been alleging, he and his legal team have been working to cast doubt on the integrity of the vote.
Mr Biden won by wide margins in both the Electoral College and popular vote, where he received nearly 80 million votes.
Asked whether he would vacate the building and allow a peaceful transition of power in January, Mr Trump said: "Certainly I will. But you know that."
"This has a long way to go."
Mr Trump's administration has already given the green light for a formal transition to get underway, but he took issue with Mr Biden moving forward.
But he has made it clear that he will likely never formally concede, even if he said he would leave the White House.
"It's gonna be a very hard thing to concede. Because we know there was massive fraud," he said, noting that, "time isn't on our side".
Asked whether he would attend Mr Biden's inauguration, Mr Trump said he knew the answer but did not want to share it yet.
But there were some signs that Trump was coming to terms with his loss.
At one point he urged reporters not to let Mr Biden take credit for pending coronavirus vaccines.
"Don't let him take credit for the vaccines because the vaccines were me and I pushed people harder than they've ever been pushed before," he said.
As for whether or not he plans to formally declare his candidacy to run again in 2024 - as he has discussed with aides - Mr Trump he did not "want to talk about 2024 yet".
All states must certify their results before the Electoral College meets on December 14, and any challenge to the results must be resolved by December 8.