Public debt and deficit: what one says about the other

At the end of 2025, France's public debt stood at €3,460.1bn, or 115.7% of gross domestic product (GDP), and the year's public deficit at €151.6bn, or 5.1% of GDP. Divided by the population, the debt represents €50,087 per inhabitant. These three figures come from the national accounts published by the Institut national de la statistique et des études économiques (INSEE), and they are provisional: the 2025 vintage will be revised in spring 2027.

The question this page asks is more precise than an amount: why does debt not rise by exactly the sum of deficits? And what is debt per head really worth — a figure that strikes the mind but is not repaid like a bill?

In 1981, public debt was worth €114.3bn, or 22.6% of the GDP of the time (€504.7bn). In 2025 it reaches €3,460.1bn for a GDP of €2,991.1bn. The ratio has therefore gained 93.1 points of percentage in forty-four years, and the stock has been multiplied by more than thirty in current euros — a comparison that mixes inflation, growth and real borrowing, and must be read with that caveat.

The deficit, for its part, has never been zero over the period: every year since 1981, general government — central government, local authorities and social security together — has spent more than it collected. The low point is 1.3% of GDP in 2000; the high point, 8.9% in 2020. Out of forty-five vintages, 27 exceed the three per cent of GDP threshold that the Maastricht Treaty set as a reference.

The sum of deficits from 1982 to 2025 is €3,110.0bn. Over the same period, the debt stock rose by €3,345.8bn. The difference, €235.8bn, or 7.0% of the total rise, is what national accountants call the stock-flow adjustment: the share of the change in debt that the deficit does not explain.

Two steps dominate the series. The financial crisis pushes the ratio up by 14.3 points of percentage between 2008 and 2009, the largest annual rise before 2020. Then the pandemic: the deficit reaches €207.1bn in 2020 (8.9% of GDP) and the ratio moves from 98.2% to 114.9%, because the numerator rises while the denominator — GDP — falls.

Since 2019, cumulated deficits amount to €970.7bn and debt has risen by €1,072.7bn: the gap, €102.0bn, or 9.5% of the rise, is slightly larger in proportion than over the whole period. The recent rise in debt remains, for more than nine tenths, that of the deficits.

The relationship between deficit and debt is an accounting one, not an economic one: a deficit must be financed, and it is financed by new debt. But the stock-flow adjustment shows that other operations weigh on the stock without going through the deficit — the State may borrow to acquire a financial asset (an equity stake, a loan to another body), or see the value of some securities move with interest rates and inflation. These operations explain why, in a given year, debt rises more, or less, than the deficit.

Debt per head links the stock to the population: €2,057 in 1981, €50,087 in 2025, a factor of 24.3. It is a useful order of magnitude to picture the stock, not an individual claim: the debt is carried by general government as a whole, repaid by future taxes and rolled over at maturity, never called on any inhabitant.

Three episodes structure the path. The 1993 recession, with a deficit above six per cent of GDP, opens the first decade of strong increase in the ratio. The 2008-2009 financial crisis more than doubles the deficit in one year and takes the ratio past the eighty per cent mark. The 2020 pandemic, finally, combines a record deficit with a fall in GDP: it is the only year in which the ratio gains more than fifteen points at once.

Conversely, the only decade in which the ratio falls durably is the late 1990s: between 1999 and 2001 the deficit drops below two per cent of GDP and nominal growth does the rest. It is the episode showing that the ratio can fall without net repayment, simply because the denominator runs faster than the numerator.

The latest quarterly observation puts debt at €3,595.5bn, or 119.0% of GDP, at the end of the second quarter of 2026. The 2025 deficit, 5.1% of GDP, remains above the three per cent threshold for the sixth consecutive year. The resident population is 69.1 million on 1 January 2026: that is the denominator of 2025 debt per head, a stock dated 31 December divided by the population measured the next day.