The National Debt

Why the big number isn’t the scary part

A government’s debt doesn’t work like an individual’s, and the difference is the whole point. It’s never actually paid off — the government rolls it forward, selling new bonds to retire old ones as they come due, and it has run a debt in all but a handful of years since 1837. It also borrows almost entirely in its own currency, dollars it issues itself — so unlike a household, or a country that owes in someone else’s currency, it can’t be forced into default just by running short of cash.

So the raw balance, by itself, says surprisingly little. The number that actually tells you something is the cost to carry the debt — the interest — set against the size of the economy that pays for it. If that cost climbs faster than the economy, the debt is getting harder to carry; if it doesn’t, the balance can keep rising for years without much trouble. “Is the cost growing faster than the economy?” has an actual answer — and it’s the one worth watching.

What it costs, over time

This is the chart that matters: federal interest, measured against the size of the economy, back to 1940. It fell for most of the 1990s and 2000s as rates drifted down — then turned sharply higher as the Fed raised rates and the debt kept growing. At 3.2% of GDP it’s now the most since 1991. Two forces drive it: how much is owed, and what it costs to roll that debt over — and that cost isn’t a single rate. The government borrows across the whole range of Treasuries, from short-term bills to 30-year bonds, all set in the same bond market that prices the 10-year behind your mortgage rate. When borrowing got more expensive for the government, it got more expensive for you too.

The debt is just Treasuries

Here’s the part that makes the whole thing less abstract: the national debt isn’t a number sitting in a ledger somewhere — it’s a pile of Treasury bonds. Every time the government spends more than it collects, it covers the gap by selling IOUs — Treasury bills, notes, and bonds. That yearly gap is the deficit; stack up every annual deficit, add the interest owed on the pile, and you get the debt. The deficit is this year’s shortfall, the debt is every past shortfall added together. Add up every IOU still outstanding, and that is the $39.3 trillion. “The debt” and “Treasuries” are the same thing seen from two sides.

That’s also why the cost climbs the way it does. The interest the government pays is simply the yield on those Treasuries — the same rates we track on the Yields page, where inflation, how much the government is borrowing, and even geopolitics all push yields up or down. As older bonds from the cheap-money years mature, the government has to replace them by selling new ones at today’s higher yields — so the average rate it pays keeps grinding upward, even on debt it already owed.

And one friendly twist the doom version skips: you’re probably on the lender’s side of this. Treasuries are the backbone of money-market funds, bond funds, and the “safe” slice of most 401(k)s — so a piece of “the national debt” is very likely an asset in your own retirement account.

The headline, defused

That $39.3 trillion isn’t one thing. About a fifth of it is one part of the government owing another:

Who actually owns it?

Here’s the question behind a thousand scary headlines — and the answer almost nobody leads with. Of the $31.6 trillion held by the public, about $9.3 trillion is owned abroad. The other ~70% is owned right here at home — U.S. households, banks, pension and mutual funds, insurers, and the Federal Reserve, including the bond slice of your own 401(k). Most of the national debt is owned by Americans.

Here’s the data that defuses the always-floated headline that a foreign country “owns us.” The largest foreign holders, March 2026:

U.S. Treasury (TIC), March 2026 — reported with a ~2-month lag, so this panel carries its own date, separate from the daily $39.3T total above.

What the debt is made of

Strip it down and the debt is a short list of products. The part that trades in markets — about $30.9 trillion of the total — is mostly Notes and Bills:

Marketable Treasuries only (~$30.9 trillion); the other ~$8.4 trillion is mostly the trust-fund IOUs from the split above. “Avg. rate paid” is what the Treasury actually pays on each type right now. † TIPS’ rate is only the coupon — the government also pays inflation through a rising principal, so it isn’t really cheaper than the rest. (U.S. Treasury, 2026-05.)

The honest measure

The raw $39.3 trillion only means something next to the economy that backs it. The measure economists use for the burden is debt held by the public — the part actually borrowed in open markets — set against GDP, and right now that’s about 98%: just under a full year of everything the country produces. The chart goes back to 1939, and the arc is the point: the debt spiked to fund World War II, peaking near 106% of GDP in 1946, then shrank for three decades as the economy outgrew it, and has climbed back since — though it remains below that postwar record. The country has carried a load like this once before and grown its way back down.

You’ll also see a bigger figure quoted — around 121%. That’s gross debt, which adds back the intragovernmental IOUs — the “money we owe ourselves” from earlier. It’s a real total, but the publicly-held share is the one that measures what the government has actually borrowed from the economy.