Just hours before the third Democratic presidential primary debate, candidate Bernie Sanders released details about his proposed single-payer health-care plan. (Sarah Parnass/The Washington Post)

CHARLESTON, S.C. -- Democratic presidential hopeful Bernie Sanders would raise income taxes across the board -- and by substantially more on high earners -- to pay for an ambitious single-payer health-care plan, under details released Sunday night.

The senator from Vermont said the $1.38-trillion-a-year plan, which was outlined before a Democratic debate here, would ultimately save most families thousands of dollars a year on out-of-pocket health-care costs.

Sanders would pay for it largely through higher income taxes. Those making more than $250,000 a year would pay a marginal tax rate of 37 percent, up a few percentage points from what they now pay.

Sanders would add three more tax brackets, with marginal rates topping out at 52 percent for those making $10 million a year -- significantly more than the current top rate of 39.6 percent.

[Sanders says he’ll detail costs of his universal health-care plan before voting begins]

A shift to Sanders’s “Medicare for all” program also would mean that Americans would pay a 2.2 percent health-care premium, calculated based on their federal income taxes. And employers would pay a new 6.2 percent payroll tax. Economists say payroll taxes are usually passed along to workers.

The plan also would be funded in part by an increase in estate taxes on wealthy Americans, as well as a change in the way capital gains and dividends are taxed, the senator said.

Sanders has long argued that most families would pay substantially less out of pocket for health care under his approach.

On Sunday, he released figures from an economist suggesting that a family earning $50,000 a year would save nearly $6,000 a year on health-care costs. The cost of the new federal health-care premium would be more than offset by what such families would save on private premiums and deductibles, according to the analysis by Gerald Friedman, an economist at the University of Massachusetts at Amherst.

Friedman estimated that Sanders's Medicare-for-all plan would save $6 trillion over the next 10 years compared with the current system, in large part by eliminating what the Sanders campaign described as "expensive and wasteful private health insurance."

[Sanders says he’s ‘very healthy’ amid reports that Clinton ally is seeking medical records]

“Universal health care is an idea that has been supported in the United States by Democratic presidents going back to Franklin Roosevelt and Harry Truman,” Sanders said in a statement. “It is time for our country to join every other major industrialized nation on earth and guarantee health care to all citizens as a right, not a privilege.”

Sanders released the details of his plan about two hours before the scheduled start of a debate with former secretary of state Hillary Clinton and former Maryland governor Martin O'Malley.

Shortly before the debate started, the Clinton campaign released a statement criticizing the timing of Sanders's announcement.

"When you’re running for president and you’re serious about getting results for the American people, details matter— and Senator Sanders is making them up as he goes along," Clinton spokesman Brian Fallon said in a statement.

As polls in the early nominating states have tightened, Clinton had stepped up pressure on Sanders to detail how he would pay for a single-payer system, which he has long advocated.

As a senator, Sanders introduced legislation in 2013 to move the country to a similar program. The costs to businesses are somewhat less in what he is proposing as a presidential candidate.

In a Facebook post earlier Sunday, former labor secretary Robert Reich said that he had gotten an advance look at the plan and that it “isn’t nearly as radical as will be portrayed.”

It builds on the strengths of Medicare,” Reich wrote. “Like Medicare, it's universal -- separating health insurance from employment, and enabling people to choose a health care provider without worrying about whether that provider is in-network: All they’d need do is go to the doctor and show their insurance card. No more copays, no more deductibles and no more fighting with insurance companies when they fail to pay for charges.”