The Interest Bill Comes Due: America’s Debt Math in 2026

Somewhere in the last few years, interest on the national debt stopped being an abstraction on a chart and became one of the largest line items in the federal budget. By fiscal year 2026, net interest payments trail only Social Security among all federal spending categories — ahead of national defense, ahead of Medicare [1]. The government is not paying down its debt; it is increasingly borrowing simply to cover the interest on what it already owes.

The numbers, plainly stated

The federal government paid $970 billion in interest costs in 2025, a figure that has roughly doubled in just three years, after reaching an inflation-adjusted-record $476 billion in 2022 [1]. In dollar terms, that trajectory has not slowed: the Congressional Budget Office’s own baseline projects net interest payments rising from about $1.0 trillion in 2026 to $2.1 trillion by 2036, totaling $16.2 trillion cumulatively over the decade [1]. Relative to the size of the economy, interest costs are set to reach 3.2% of GDP in 2026 — surpassing the previous post-World War II high set in 1991 [1].

The pace within fiscal 2026 has borne this out. In the first quarter of the fiscal year alone (October–December 2025), net interest payments totaled $270.3 billion, and interest costs consumed 44.5% of that quarter’s total deficit — up from 34% of the deficit in the same period the year prior [2]. By the eighth month of FY2026 (through May), cumulative interest payments were running 8.8% higher than the prior year, driven by both a larger debt stock and elevated long-term rates [3]. Total debt held by the public reached $31.5 trillion by the end of May 2026, itself $2.6 trillion higher than a year earlier [4].

Why the interest bill keeps climbing

Two forces are compounding each other. First is simple arithmetic: the debt itself keeps growing, because the government continues to run a structural primary deficit — spending more than it collects even before accounting for interest [1]. The Congressional Budget Office’s most recent long-term outlook, based on laws in place as of January 2026, projects the total deficit rising from 5.8% of GDP in 2026 to 6.7% by 2036, pushing debt held by the public to $56 trillion — 120% of GDP — by the end of that period, more than double the 50-year historical average of 51% [5].

Second is the interest rate environment itself. Deloitte’s analysis notes total outstanding federal debt near $36 trillion, nearly 20% higher than U.S. nominal GDP and larger than the combined output of the next four biggest economies [6]. A significant share of that debt was issued cheaply during the pandemic-era low-rate period and is now rolling over into a higher-rate world: by the end of 2025, roughly a third of marketable debt — $9.2 trillion — had matured, with another $9 trillion set to mature in 2026 [6]. Each dollar of that maturing debt gets refinanced at whatever the prevailing rate happens to be, and 10-year Treasury rates averaged 4.1% through the first quarter of FY2026, up from 4.06% to 4.14% between October and December alone [2].

Cracks in demand

There are signs the bond market itself is growing more skeptical of absorbing an ever-larger supply of Treasury debt. A series of weak Treasury auctions in March 2026 fed concerns about softening demand: primary dealers — the banks obligated to help ensure auctions clear — were forced to absorb 24% of a two-year note auction, roughly double their normal share, with five- and seven-year securities seeing similarly weak uptake [7]. Treasury’s own quarterly refunding estimates show borrowing needs continuing to climb, with $671 billion in privately-held net marketable debt expected to be issued in the final quarter of FY2026 alone — $79 billion more than had been estimated just months earlier [7].

The fiscal year’s overall deficit is now expected to land at roughly $2 trillion, according to both the Treasury Department and bond market consensus — up from the $2.1 trillion figure the White House projected in its own budget request and above the Congressional Budget Office’s earlier $1.8 trillion estimate from February [8]. As Maya MacGuineas of the Committee for a Responsible Federal Budget put it, deficits of this size “used to be unheard of, and then they only occurred during major recessions” — and are now simply the norm [8]. Debt-to-GDP crossed 100% in March 2026, and the CBO projects it will surpass the historic 1946 post-war high of 106% by 2030 [8].

Who is exposed

Roughly 29% of U.S. Treasury debt — about $8.5 trillion as of 2024 — is held by foreign investors, with Japan the single largest holder at $1.1 trillion, followed by China at $800 billion, down from a peak of $1.3 trillion in 2013 [6]. That composition matters because it means confidence in U.S. fiscal management is not purely a domestic political question — it is priced, continuously, by a global pool of buyers who have other places to put their money. Rising tariff revenue has offered the federal government some fiscal relief on the margins, but frequent shifts in tariff policy — including a Supreme Court ruling that some tariffs imposed under the International Emergency Economic Powers Act were illegal, triggering $166 billion in refunds to businesses — have simultaneously undermined the predictability that helps sustain global confidence in Treasuries and the dollar [6] [9].

The structural bind

None of this reflects a single bad budget year; it reflects a widening gap between what the government spends and what it collects, compounded by a debt stock that is both larger and now refinancing at higher rates than it was built on. The CBO is explicit about the consequence path: continued growth in debt relative to GDP would raise borrowing costs throughout the entire economy, not just for the federal government, crowding out private investment over time [5]. Fixing the trajectory, per CBO’s own modeling, would require a combination of roughly 2 percentage points of GDP in additional fiscal consolidation sustained over several years — a mix of tighter spending and stronger revenue collection that has, so far, remained more a matter of projection than of enacted policy [5].

References

1. Peterson Foundation. (2026, April 13). Interest Costs on the National Debt. https://www.pgpf.org/programs-and-projects/fiscal-policy/monthly-interest-tracker-national-debt/
2. EPIC for America. (2026, January 21). Interest Spending Tracker: Q1 of FY 2026. https://epicforamerica.org/federal-budget/interest-spending-tracker-q1-of-fy-2026/
3. American Action Forum. (2026, June). Debt and Deficit (Lack of) Progress Report: May 2026. https://www.americanactionforum.org/insight/debt-and-deficit-lack-of-progress-report-may-2026/
4. American Action Forum. (2026, June). Debt and Deficit (Lack of) Progress Report: May 2026. https://www.americanactionforum.org/insight/debt-and-deficit-lack-of-progress-report-may-2026/
5. Congressional Budget Office. The Budget and Economic Outlook: 2026 to 2036. https://www.cbo.gov/publication/62105
6. Deloitte Insights. (2025, September 30). US national debt fiscal effects. https://www.deloitte.com/us/en/insights/topics/economy/spotlight/us-national-debt-fiscal-effects.html
7. Bipartisan Policy Center. Deficit Tracker. https://bipartisanpolicy.org/report/deficit-tracker/
8. Fox Business. (2026, May 20). US federal deficit projected to hit $2 trillion in fiscal year 2026. https://www.foxbusiness.com/economy/federal-budget-deficit-projected-hit-2-trillion-fiscal-year-ranking-among-largest-us-history
9. Fortune. (2026, January 12). Treasury spent $276 billion in interest on the national debt in the final three months of 2025. https://fortune.com/2026/01/12/treasury-national-debt-interest/