WASHINGTON – The federal budget deficit will slip to $333 billion this fiscal year from $412 billion in 2004, as a surge of unanticipated tax receipts pushes the tide of red ink significantly below levels projected just five months ago, White House officials said yesterday.

The White House’s mid-year budget forecast also shows that President Bush is on track to reach his goal of cutting the deficit in half a year before his promised deadline of 2009. By 2008, the White House forecasts that the deficit will have fallen to $162 billion, or 1.1% of the gross domestic product. A slight rise projected for 2010 reflects the initial costs of Mr. Bush’s proposal to add private investment accounts to Social Security.

“It’s a sign that our economy is strong, and it’s a sign that our tax relief plan, our pro-growth policies, are working,” Mr. Bush said after meeting with his cabinet at the White House.

In dollar terms, the 2005 deficit of $333 billion will still be the third highest on record. That total figure relies on the expenditure of about $173 billion in surplus Social Security taxes that must be repaid when the baby boom generation enters its retirement years. Senator DeMint, a Republican of South Carolina, called the deficit numbers “misleading,” since “Congress is raiding Social Security to mask the true size of the deficit.”

But the change from February’s projections is dramatic. Then, the White House foresaw a record $427 billion deficit, equal to 3.5% of GDP. Under that forecast, the deficit would have risen for the fourth straight year, from the $128 billion surplus Mr. Bush inherited in 2001. Now, the deficit is expected to finally begin receding, and it would come in at 2.7% of the GDP, smaller in those terms than the deficits of 15 of the past 25 years.

“The U.S. budget deficit is falling, and it’s falling fast,” said Joshua Bolten, the White House budget director.

Independent budget experts cautioned that a number of debatable assumptions underpin the White House’s deficit projections in future years. The improved budget picture for 2005 is almost all the result of an $87 billion surge in unforecasted tax receipts, much of which may have resulted from one-time events, such as a one-year corporate tax holiday enacted last year and stock market gains in 2004 that have not continued in 2005, some economists say.

Congressional Budget Office Director Douglas Holtz-Eakin said last week that such events will not likely make much difference for the budget picture by the end of the decade. But the White House assumes that tax receipts will come in an average of $82 billion higher in each of the next five years than the administration forecasted in February. A White House budget official called the decision “eminently reasonable.”