The president’s plan would raise $320 billion over the next decade, while adding new provisions cutting taxes by $175 billion over the same period. The revenue generated would also cover an initiative Mr. Obama announced this month, offering some students two years of tuition-free community college, which the White House has said would cost $60 billion over 10 years.

The centerpiece of the plan, described by administration officials on the condition of anonymity ahead of the president’s speech, would eliminate what Mr. Obama’s advisers call the “trust-fund loophole,” a provision governing inherited assets that shields hundreds of billions of dollars from taxation each year. The plan would also increase the top capital-gains tax rate, to 28 percent from 23.8 percent, for couples with incomes above $500,000 annually. 

Those changes and a new fee on banks with assets over $50 billion would be used to finance a set of tax breaks for middle-income earners, including a $500 credit for families in which both spouses work; increased child care and education credits; and incentives to save for retirement.