WASHINGTON  For his first annual budget next week, President Obama has banned four accounting gimmicks that President George W. Bush used to make deficit projections look smaller. The price of more honest bookkeeping: A budget that is $2.7 trillion deeper in the red over the next decade than it would otherwise appear, according to administration officials.

The new accounting involves spending on the wars in Iraq and Afghanistan, Medicare reimbursements to physicians and the cost of disaster responses.

But the biggest adjustment will deal with revenues from the alternative minimum tax, a parallel tax system enacted in 1969 to prevent the wealthy from using tax shelters to avoid paying any income tax.

Even with bigger deficit projections, the Obama administration will put the country on “a sustainable fiscal course” by the end of Mr. Obama’s term, Peter R. Orszag, the director of the Office of Management and Budget, said Thursday in an interview. Mr. Orszag did not provide details of how the administration would reduce a deficit expected to reach at least $1.5 trillion this year.