Interest expense on U.S. federal debt, monthly
Monthly interest expense on U.S. federal debt outstanding, by category (public issues vs. government account series), group and type — current-month and fiscal-year-to-date amounts in dollars. History from 2010-05.
Source: U.S. Department of the Treasury — Fiscal Data14,642 rowsUpdated: 9/22/2026
interestdebtfiscalusdebt-service
Quality
100
Attribution
U.S. Department of the Treasury, Bureau of the Fiscal Service, Fiscal Data
Schema
| Column | Type | Description |
|---|---|---|
| date | timestamp | Month of observation, mapped to the first day of the month from the provider's Record Date ("The date that data was published"). Debt to the Penny is published daily; MTS, average interest rates and interest expense are published monthly at month-end. |
| series_id | string | Stable machine identifier for the series. Built from the provider's own description fields (never the classification_id, which the MTS dictionary notes changes with every publication): debt measures use short slugs of the provider's Display Names; MTS uses monthly_/fytd_/fy_ prefixes; interest-rate and interest-expense series slug the provider's type/group descriptions. |
| series_label | string | Human-readable series name using the provider's own wording (Display Names and description fields from the Fiscal Data data dictionaries), e.g. "Debt Held by the Public" or "Marketable — Treasury Bills". |
| unit | string | Unit of value: "USD" for dollar amounts (the provider's CURRENCY data type) or "%" for rates (the provider's PERCENTAGE data type, percent per annum). |
| value | float | Observed value as a number. Fiscal Data returns missing observations as the string "null"; these become null here. For the MTS deficit/surplus series a positive value means a deficit (outlays exceeded receipts). |
Sample rows
| date | series_id | series_label | unit | value |
|---|---|---|---|---|
| 2011-10-01T00:00:00 | interest_expense_on_govt_account_series_accrual_basis_gas_expense_department_of_defense_amortized_discount_premium__fytd | Interest Expense On Govt Account Series — Accrual Basis Gas Expense — Department Of Defense Amortized Discount (Premium) — fiscal year to date | USD | -436156509.27 |
| 2011-11-01T00:00:00 | interest_expense_on_govt_account_series_accrual_basis_gas_expense_department_of_defense_amortized_discount_premium__fytd | Interest Expense On Govt Account Series — Accrual Basis Gas Expense — Department Of Defense Amortized Discount (Premium) — fiscal year to date | USD | -868945777.44 |
| 2011-12-01T00:00:00 | interest_expense_on_govt_account_series_accrual_basis_gas_expense_department_of_defense_amortized_discount_premium__fytd | Interest Expense On Govt Account Series — Accrual Basis Gas Expense — Department Of Defense Amortized Discount (Premium) — fiscal year to date | USD | -1316773028.91 |
| 2012-01-01T00:00:00 | interest_expense_on_govt_account_series_accrual_basis_gas_expense_department_of_defense_amortized_discount_premium__fytd | Interest Expense On Govt Account Series — Accrual Basis Gas Expense — Department Of Defense Amortized Discount (Premium) — fiscal year to date | USD | -1766186318.69 |
| 2012-02-01T00:00:00 | interest_expense_on_govt_account_series_accrual_basis_gas_expense_department_of_defense_amortized_discount_premium__fytd | Interest Expense On Govt Account Series — Accrual Basis Gas Expense — Department Of Defense Amortized Discount (Premium) — fiscal year to date | USD | -2188062266.13 |
Download sample data
Download the full sample snapshot for this dataset (sample rows, not the complete dataset).
Use with an LLM
Point any LLM at the metadata endpoint — the documentation above is machine-readable too (JSON-LD + Croissant).
cURL
curl "https://datazimuts.com/v1/datasets/treasury/treasury_interest_expense" | jq '{title, rows, columns_count, license}'Python
import requests
ds = requests.get("https://datazimuts.com/v1/datasets/treasury/treasury_interest_expense").json()
print(ds["title"], ds["rows"], "rows")
# Sample rows for an LLM context window
for row in ds.get("sample_rows", [])[:5]:
print(row)API endpoint: https://datazimuts.com/v1/datasets/treasury/treasury_interest_expense
Tip: fetch /llms.txt for the full machine-readable catalog.