The deficit was being driven to an all-time high by the sagging economy and stimulus payments made to 130 million households in an effort to keep the country from falling into a damaging recession, the administration said.
But the deficit could soar even higher if the economy does worse than the White House expects.
The Office of Management and Budget cited the "recent economic slowdown" in unveiling updated deficit projections in the official budget.
The budget office predicts the economy will grow at a rate of 1.6 percent this year and will rebound to a 2.2 percent growth rate next year. That's a half percentage point higher than predicted but also the widely cited "blue chip" consensus of leading economists, the Associated Press reported. The administration also sees inflation averaging 3.8 percent this year, but slowing to 2.3 percent next year - better than the 3 percent seen by the blue chip panel.
"The nation's economy has continued to expand and remains fundamentally resilient," said the budget office report.
A $482 billion deficit, however, would easily surpass the record deficit of $413 billion set in 2004.
Additionally, the new figure underestimates the deficit because it leaves out about $80 billion in war costs. In a break from tradition - and in violation of new mandates from Congress - the White House did not include its full estimate of war costs, the AP reported.
In February, the White House forecast that next year's deficit would be $407 billion, which puts the increase in the projections at $72 billion.
Figures for the 2008 budget year ending Sept. 30 will actually drop from an earlier projection of $410 billion to $389 billion, the report said.
The White House still projects that the U.S. will enjoy a budget surplus by 2012. The deficit numbers for 2008 and 2009 represent about 3 percent of the size of the economy, which is the measure seen as most relevant by economists. That's considerably smaller than the deficits of the 1980s and early 1990s, when Congress and earlier administrations cobbled together politically painful deficit-reduction packages.
Still, the new figures are so eye-popping in dollar terms that it may restrain the appetite of the next president to add to it with expensive spending programs or new tax cuts. In fact, pressure may build to allow some tax cuts enacted in 2001 and 2003 to expire at the end of 2010, with Congress also feeling pressure to curb spending growth.
The deficit for 2007 totaled $161.5 billion, which represented the lowest amount of red ink since an imbalance of $159 billion in 2002. The 2002 performance marked the first budget deficit after four consecutive years of budget surpluses.
That stretch of surpluses represented a period when the country's finances had been bolstered by a 10-year period of uninterrupted economic growth -- the longest in U.S. history.
In his first year in office, helped considerably by projections of continuing surpluses, President Bush drove through a 10-year, $1.35 trillion package of tax cuts. But the country fell into a recession in March 2001 and government spending to fight terrorism contributed to pushing the deficit to a record in dollar terms in 2004.
House Budget Committee Chairman John Spratt, D-S.C., said the new deficit figure confirms "the dismal legacy of the Bush administration: under its policies, the largest surpluses in history have been converted into the largest deficits in history," according to the AP.
White House spokeswoman Dana Perino said earlier that a bigger deficit is "the price that we pay in order to help improve the economy," Agence France-Presse reported.
But she said the administration still stood by its goal of achieving a balanced budget by 2012.
"We hope to pull out of this economic downturn over the next few months because of the stimulus package," she added.