Gross interest expense on Treasury debt (FY2027 to date)

How it's calculated. One measure throughout: Treasury's monthly interest expense on all Treasury securities (accrual basis, including interest credited to trust funds and amortized discounts). FY2027 to date starts at $0 on Oct 1 and ticks at the last 12 reported months' total ($1,360.4B/yr, 2025-10 to 2026-09), which is also the official FY2026 total ($1,360.4B). Larger than 'Net interest' (budget function 900) because interest paid to trust funds nets out there, and different from cash interest paid on the DTS.

Source. Treasury, Interest Expense on the Public Debt Outstanding, official as of Oct 1, 2026.

* Per person (projected population) divides by the US population projected to now: the official Census Vintage 2025 estimate for July 1, 2025 (341,784,857), projected forward at Census's stated growth rate (343,051,422 at build time). Per tax return filed divides by 162,754,810 individual income tax returns filed in FY2025 (IRS Data Book, Table 1-2); a joint return counts once and returns with zero tax liability are included.