The debt was $10.626 trillion on the day Mr. Obama took office. The latest calculation from Treasury shows the debt has now hit $14.639 trillion.
It's the most rapid increase in the debt under any U.S. president.
The national debt increased $4.9 trillion during the eight-year presidency of George W. Bush. The debt now is rising at a pace to surpass that amount during Mr. Obama's four-year term.
Mr. Obama blames policies inherited from his predecessor's administration for the soaring debt. He singles out:
He goes on to blame the recession, and its resulting decrease in tax revenue on businesses, for making fewer sales, and more employees being laid off. He says the recession also resulted in more government spending due to increased unemployment insurance payments, subsidies to farms and funding of infrastructure programs that were part of his stimulus program.
At the first town hall meeting of his Midwestern bus trip last week, Mr. Obama told an audience in Minnesota that "the debt problem is real and the deficit problem is real."
But he also called in "a manageable problem."
The Gross National Debt now stands at 97.6 percent of the nation's Gross Domestic Product - the total value of goods and services produced by labor and property in the U.S.
Facts about the debt