WASHINGTON — As House Democrats geared up for a possible vote on Sunday to pass health care legislation, the Congressional Budget Office issued an analysis allowing them to point to significant cost savings in the decades ahead, and President Obama postponed a planned trip to the Pacific to keep pressing for approval.

The House Democratic leader, Rep. Steny H. Hoyer of Maryland, said that the nonpartisan budget office had determined that the package of legislation, which would cost about $940 billion over ten years, would produce “the largest deficit reduction of any bill we have adopted in Congress since 1993,” when it passed tax increases sought by President Clinton.

In the first ten years, the health legislation would reduce deficits by $138 billion,and the effect on deficits over the following decade would be much greater — Democrats said $1.2 trillion — although such long-term forecasts are more speculative. The savings would come largely from reductions in the growth of Medicare spending, with new fees and tax increases also contributing.

The cost savings are “but one virtue of a reform that will bring new accountability to the insurance industry and greater economic security to all Americans,” President Obama said at a ceremony where he signed a new jobs bill into law. “So I urge every member of Congress to consider this as they prepare for their important vote this weekend.”