Biden's student loan relief plan will cost $400 billion. Republicans call it 'unsustainable' and Democrats say it will give 'Americans more breathing room.'

• A new report from the Congressional Budget Office finds student loan relief will cost $400 billion.
• That figure also doesn't account for losses from reforms to income-driven repayment plans.

At the end of August, President Joe Biden finally fulfilled a long-awaited campaign promise, and canceled up to $20,000 in student loan debt for some borrowers — a move that immediately drew ire from the right over its fairness and potential cost.

Now, the nonpartisan Congressional Budget Office is shedding light on how much relief will cost: $400 billion, plus $20 billion from outstanding loan payments and interest being paused through December. That $400 billion comes from the difference between how much borrowers were expected to repay before cancelation was announced, versus how much they'll pay now, with the CBO's data projecting the potential impact over the next 30 years.

The figure is "even worse than we thought," Marc Goldwein, senior vice president for policy at the Committee for a Responsible Federal Budget, told Insider. "This is only the debt cancellation. This does not account for the income driven repayment reforms."

"It's almost unthinkable that the administration would announce such a large policy and not even know, or not even tell us how much it costs — particularly, we're talking about something that costs 400 billion dollars plus," Goldwein said.

It's a figure that will likely stoke continued GOP concerns over the cost of Biden's policy. The CBO estimates come partially in response to questions raised by Reps. Virginia Foxx and Richard Burr. Foxx, a Republican from North Carolina, has been an outspoken opponent of Biden's relief plan — and previously introduced legislation to preemptively block it.

The estimate "shows this administration has lost all sense of fiscal responsibility," the Republican from North Carolina said in a statement. "Rather than working with Congress to bring down college costs, President Biden has opted to bury the American people under our unsustainable debt," Foxx said.

However, the Government Accountability Office found in July that the government was already losing money on federal student loans partially due to pandemic-related pauses, even before Biden announced cancelation. The $400 billion also pales in comparison to major expenditures from the administration, like $796 billion on defense in 2022.

The student loan relief will disproportionately impact Black and Latino borrowers, millennials, and public servants such as teachers, police, and non-profit workers. A Census Bureau report found that Black and Hispanic women will see the biggest reductions among borrowers holding student loans, with 5.4% and 4.7% respectively seeing their loans completely wiped. Borrowers who will see their debts wiped completely previously told Insider that the relief is life-changing.

"Today's CBO estimate makes clear that millions of middle class Americans have more breathing room thanks to President Biden's historic decision to cancel student debt," Sens. Elizabeth Warren and Chuck Schumer — two Democrats who have been on the frontlines of pushing for broader relief — said in a joint statement.

"We don't agree with all of CBO's assumptions that underlie this analysis," they said, "but it is clear the pandemic payment pause and student debt cancellation are policies that demonstrate how government can and should invest in working people, not the wealthy and billionaire corporations."