U.S. National Debt Crosses $40 Trillion

The Treasury publishes the total public debt outstanding every business day in a series called Debt to the Penny. On Monday 17 August 2026 the figure was $39,986,657,878,071.92. On Tuesday 18 August it was $40,047,425,768,420.22, a rise of $60.8 billion in one day and the first reading in the history of the series above $40 trillion.

The pace behind the crossing is the more useful figure. A year earlier, on 18 August 2025, the same series read $37,144,076,750,410.16. The increase over twelve months is $2.90 trillion, which is $7.954 billion a day. The round numbers now in circulation, $3 trillion and nearly $8 billion a day, are close to the record, though the first rounds up by about $97 billion.

Measured by milestones, the borrowing looks steady rather than accelerating. The total first exceeded $38 trillion on 21 October 2025, $39 trillion on 17 March 2026 and $40 trillion on 18 August 2026. The first of those trillions took 147 days and the second took 154 days.

That total is the whole debt. It divides into $32.27 trillion held by the public and $7.78 trillion of intragovernmental holdings, which are the balances the Treasury owes to federal trust funds.

One caveat on the twelve-month rate

The pace claim needs a caveat, and the caveat is visible in the same series. Between 2 January and 2 July 2025 the total moved from $36,169,957,618,760.21 to $36,213,797,741,182.40. That is a rise of $43.8 billion over six months, because the statutory debt limit was binding and the Treasury was operating under extraordinary measures. Any twelve-month comparison that begins inside that flat stretch will overstate the underlying rate of borrowing. The window used here begins on 18 August 2025, after the total had already resumed climbing, so it is not inflated by the catch-up.

Interest and defense, stated on one basis

The milestone has arrived alongside a second claim, that interest now costs more than defense. That claim is correct. It is usually dated wrongly, and it is almost always stated without saying which interest and which defense are meant. The two choices give materially different answers.

Table 9 of the Monthly Treasury Statement reports net outlays by budget function. For the first ten months of fiscal 2026, October 2025 through July 2026, net interest was $931.36 billion. National defense, budget function 050, was $803.70 billion. Net interest was 15.9 percent higher, and the gap was $127.65 billion. Both are net outlays, for the same period, from the same table, so nothing here is being compared across bases.

Gross interest is a larger number and a different one. Table 5 of the same statement shows interest on Treasury debt securities, gross, of $1,169.59 billion for the ten months. Interest received by trust funds offsets $206.69 billion of that, which leaves $962.90 billion. The net interest line in Table 9 is lower again, at $931.36 billion, because it also nets out other interest the government receives. On the gross basis, interest was 1.46 times national defense outlays. On the net basis it was 1.16 times. Either way the ranking holds, which is why the imprecision has gone unchallenged.

The crossover did not happen this year. On complete fiscal years, net interest passed national defense in fiscal 2024, when it was $881.65 billion against $874.04 billion, a margin of $7.61 billion. In fiscal 2025 the margin was $53.71 billion. Ten months into fiscal 2026 it is $127.65 billion. The gap has widened in each of the past two years, and the ten-month figure for fiscal 2026 is already more than twice the full-year margin for fiscal 2025.

Where the interest line now sits

Among the budget functions in Table 9, net interest was the third largest outlay of the first ten months of fiscal 2026. Social Security was $1,384.44 billion and Medicare was $954.52 billion. Net interest at $931.36 billion sits above Health at $845.18 billion and above national defense. Against total receipts of $4,485.42 billion for the same ten months, net interest absorbed 20.8 cents of every dollar the government collected.

Year on year, net interest rose 10.8 percent and national defense rose 6.0 percent. The average interest rate on total interest-bearing debt was 3.447 percent at the end of July 2026 against 3.352 percent a year earlier, an increase of 2.8 percent. Total debt outstanding over the same twelve months rose 7.7 percent. Both the price and the quantity moved up, and the larger move was in the quantity.

The debt grew faster than the deficit

One reconciliation is worth setting out, because the two numbers are often used as though they were the same. The deficit for October 2025 through July 2026 was $1,798.82 billion. Over those same ten months, total public debt outstanding rose from $37,637,553,494,935.61 on 30 September 2025 to $39,771,617,162,466.97 on 31 July 2026, an increase of $2,134.06 billion. The debt grew by $335.25 billion more than the reported deficit.

The government's cash position does not account for it. The Treasury General Account closed at $890.8 billion on 30 September 2025 and at $876.6 billion on 31 July 2026, a fall of $14.3 billion. The deficit measures budget receipts against budget outlays. Debt outstanding also moves with transactions classified as means of financing rather than as outlays, including the financing accounts for federal direct and guaranteed loans. The Monthly Treasury Statement does not reconcile the two figures, and a reader who treats the annual change in debt as the deficit will be wrong by a few hundred billion dollars in most years.

The next statement, covering August 2026, is the one that will show what the first month above $40 trillion cost to carry.