National Budgets
OECD governments spend an average of 46% of GDP. The composition tells a deep story: pensions and health together typically consume 40-50% of total spending; defense varies from 1-5%; education 4-6%; debt service from 1-15% depending on debt level and rates. The composition shifts slowly but moves with aging, geopolitics, and crisis response.
Key insights
Aging is reshaping spending
Pensions and health spending have grown from ~25% (1970s) to ~45% (2024) of OECD government spending. The shift has come at the expense of capital investment, education, family support, and other categories. The trend is structural and unlikely to reverse — population aging will keep pushing these shares up for decades. Some governments will accommodate the increase through tax increases; others will compress the rest of the budget.
Defense spending varies widely
Defense ranges from 5%+ of GDP (Saudi Arabia, Russia, Israel, USA pre-2010s) to under 1% (Mexico, Japan, Iceland, Costa Rica). The post-Cold-War 'peace dividend' (1989-2014) is over; NATO members targeting 2%+ have been raising spending. Germany, Poland, the Baltic states have all sharply increased after 2022. China's defense spending has tripled in real terms since 2000.
Interest costs rising fast
US federal debt service has tripled since 2020 — from ~$300B to ~$900B per year, projected to exceed $1T in 2025. This reflects: higher rates × growing debt stock × short maturity profile. Several other countries (UK, Italy, France) face similar pressure. Rising interest costs crowd out other categories and have second-order political consequences — every dollar to bondholders is a dollar not for current programs.
Government spending / GDP — selected countries (2024)
Total general government spending
Key Finding: France leads at ~57%. The US sits at 31% (federal alone), 37% combined. Singapore and Switzerland run leanest among rich countries.
US federal spending by category (FY2024)
% of total $6.75T outlays
Key Finding: Social Security, Medicare, defense, interest and Medicaid together are about 70% of federal spending.
Methodology & caveats
COFOG classification
UN Classification of the Functions of Government: 10 main divisions (general public services, defense, public order, economic affairs, environment, housing, health, recreation, education, social protection). Used by OECD for cross-country comparisons. National budget classifications differ — careful mapping needed for cross-country work.
Federal vs general government
US 'federal' is one of three levels (federal, state, local). General government adds state and local spending — pushing US to ~37% of GDP. EU countries usually publish 'general government' figures by default. Comparing US federal to French general government understates US public spending substantially.
Mandatory vs discretionary
US distinguishes mandatory spending (Social Security, Medicare, Medicaid, interest — set by formula, not annual appropriation) from discretionary (defense, agencies — annually appropriated). Mandatory is ~70% of spending and growing; discretionary share has been falling steadily for decades.