War costs are measured in more than battlefield operations. They include military budgets, foreign aid, veterans’ care, homeland security, borrowing costs and the economic trade-offs created when governments redirect public resources. In 2024, world military expenditure reached $2,718 billion, while U.S. estimates put the cost of post-9/11 wars through fiscal year 2022 at about $8 trillion.
Contents
- Global military spending
- Conflict-affected country budgets
- United States wartime spending
- The long tail of post-9/11 wars
- Allied aid and national responses
- Financing, procurement and trade-offs
Global military spending
According to SIPRI’s Trends in World Military Expenditure, 2024, global military expenditure rose 9.4% in 2024, the steepest year-on-year increase since at least 1988. Spending was 37% higher in 2024 than in 2015 and equaled 2.5% of global GDP. On average, military expenditure represented 7.1% of government expenditure worldwide.
The regional totals show how broadly the increase was distributed:
| Region | 2024 military expenditure | Related measure |
|---|---|---|
| Americas | $1,100 billion | 40% of world spending |
| Europe | $693 billion | Up 17% in 2024; 83% above 2015 |
| Asia and Oceania | $629 billion | Up 46% from 2015 |
| Middle East | $243 billion, estimated | Up 15% from 2023 |
The Middle Eastern figure is explicitly uncertain and excludes Syria and Yemen. SIPRI’s figures are military-expenditure statistics used here as a measurable indicator of conflict and military mobilization. Its 2024 dollar figures are current U.S. dollars, while percentage changes are expressed in constant 2023 U.S. dollars. SIPRI definitions and coverage can differ from NATO or national accounting.
Conflict-affected country budgets
The budget burden is much heavier in countries experiencing armed conflict. In 2024, countries affected by armed conflict spent an average of 4.4% of GDP on the military, compared with 1.9% in countries without armed conflict.
Ukraine spent $64.7 billion on its military in 2024. That was 34% of GDP, the highest military burden in the world, and 54% of total government spending. SIPRI reports that 100% of Ukraine’s tax revenues were absorbed by military spending, while non-military socioeconomic spending was funded by foreign aid. Ukraine received at least $60 billion in financial military aid in 2024, mostly from the United States, Germany and other European countries. Including that aid, SIPRI says Ukraine’s 2024 military spending would have totaled $125 billion.
Russia’s military expenditure reached an estimated $149 billion in 2024. It was 38% above 2023 and double its 2015 level. Military spending equaled 7.1% of Russian GDP and 19% of government expenditure.
Israel’s military expenditure grew 65% in 2024 to $46.5 billion, its largest annual increase since the 1967 Six-Day War. Its military burden rose from 5.4% of GDP in 2023 to 8.8% in 2024.
These figures describe sharply different fiscal conditions: Ukraine’s spending absorbed more than half of government expenditure, Russia’s spending represented nearly one-fifth, and Israel’s military share of national output increased substantially in one year.
United States wartime spending
The United States spent $997 billion on its military in 2024, according to SIPRI. That was a 5.7% increase in one year and 19% above the 2015 level. The United States accounted for 37% of global military expenditure, and the Department of Defense accounted for 89% of U.S. military spending.
U.S. supplemental military spending totaled $72.8 billion in 2024. Within that amount, the Department of Defense allocated $48.4 billion for Ukraine financial aid, equipment and training; $10.6 billion to support Israel; and $1.9 billion for military aid to Taiwan.
The structure of wartime funding also matters. The Congressional Budget Office’s Funding for Overseas Contingency Operations and Its Impact on Defense Spending reports that nonbase funding peaked at 28% of the Department of Defense budget in 2007 and 2008. From 2001 through 2018, nonbase funding averaged about $116 billion per year in 2019 dollars and totaled about 20% of Defense Department funding.
More than $50 billion per year of Overseas Contingency Operations funding went to enduring activities on average from 2006 through 2018. This distinction is important because a funding category created for contingencies can also support continuing defense activities.
The long tail of post-9/11 wars
The U.S. Federal Budget analysis from Brown University’s Costs of War project estimates that the United States appropriated or was obligated to spend $8 trillion on post-9/11 wars through fiscal year 2022. The estimate includes $5.8 trillion in appropriations and at least $2.2 trillion in obligations for veterans’ care over following decades.
The estimate’s components show why a war bill continues long after combat operations:
- About $2.3 trillion was spent through the Overseas Contingency Operations budget category.
- More than $1 trillion had been spent on interest payments for post-9/11 war borrowing.
- The Pentagon’s base budget increased by about $900 billion above its no-war counterfactual.
- Homeland Security spending on preventing and countering terrorism totaled more than $1.1 trillion after the Department of Homeland Security was created in 2002.
The same estimate puts U.S. spending on the war in Afghanistan at more than $2 trillion from 2001 through 2019. It puts spending and obligations for the wars in Iraq and Syria at more than $2.89 trillion from 2003 through 2023.
Future obligations are also substantial. The projected cost of caring for post-9/11 war veterans is $2.2 trillion to $2.5 trillion by 2050. Veterans’ care rose from 2.4% of the total federal budget in fiscal year 2001 to 4.9% in fiscal year 2020. Interest payments on post-9/11 war borrowing are projected to exceed $2 trillion by 2030.
These Brown Costs of War figures are estimates or obligations, not necessarily cash paid during every stated period. They include direct, indirect, veterans, homeland-security and interest components. The components should not be summed again across overlapping claims.
Allied aid and national responses
NATO’s aggregate response is large. SIPRI reports that the 32 NATO members spent $1,506 billion on their militaries in 2024, equal to 55% of world military spending. European NATO members spent $454 billion, or 30% of total NATO spending. Across all NATO members, military expenditure increased 8.9% in 2024 and 31% from 2015.
The number of members meeting the 2% benchmark also changed. Eighteen of NATO’s 32 members spent at least 2.0% of GDP on their militaries in 2024, up from 11 members in 2023.
Selected aid and commitments to Ukraine included:
- Germany provided $7.7 billion in financial military aid in 2024.
- The United Kingdom provided $3.3 billion in financial military aid in 2024.
- The United Kingdom pledged $3.8 billion per year in military aid through at least 2030.
- France’s 2024 bilateral agreement included up to $3.0 billion in additional military aid for 2024.
- Sweden established a fund for $2.4 billion in military aid between 2024 and 2026.
These are different types of figures: some are aid provided during 2024, while others are future commitments or funds covering multiple years.
Financing, procurement and trade-offs
Military costs are shaped by how governments finance and procure equipment. India earmarked 75% of capital outlays for domestic military procurement in 2024, equivalent to 22% of total military spending. Germany’s extra-budgetary military fund, created in 2022, totaled €100 billion, reported by SIPRI as $105 billion in 2022 dollars and used through 2024.
Poland spent $38.0 billion on its military in 2024, equal to 4.2% of GDP. SIPRI’s counterfactual comparisons illustrate the scale of possible changes in Europe. If European NATO members had spent 2.0% of GDP in 2024, they would have spent $33.7 billion, or 7.4%, more than their actual spending. At 5.0% of GDP, they would have spent $663 billion, or 146%, more than actual spending.
Budget choices can also shift money between policy areas. The United Kingdom planned to cut overseas development assistance from 0.5% to 0.3% of gross national income while diverting expenditure to the military. Myanmar increased military spending from 16% to 29% of government expenditure by diverting resources from social programs.
The opportunity cost can be expressed in employment estimates. Brown’s Costs of War analysis estimates that U.S. military spending produces an average of five jobs per $1 million, compared with 13 jobs per $1 million in education spending. This is an estimate for 2024, not a universal multiplier for every country or every type of military expenditure.