Defense Budget Meaning: Definition & 2025 Example ($929.2bn)
The US defense budget hit $929.2bn in 2025 — 3.12% of GDP and the largest in the world — making it the standard worked example of what "defense budget" means.
Key takeaways
- A defense budget is the funding a government allocates to its military for a given year; the US 2025 figure was $929.2bn.
- The US defense budget equals 3.12% of its GDP and ranks first in the world for 2025.
- The US accounts for 33.911% of world military spending, per our calculation from SIPRI country-level data.
- The US defense budget fell 7.5% year-on-year in 2025 and remains below its 2010 peak of $1,061.7bn.
- "Defense budget" and "military expenditure" are used interchangeably in practice, though technically the former is planned and the latter is actual spending.
Verdict
A defense budget is a government's planned annual military spending, and the US 2025 defense budget — $929.2bn, or 3.12% of GDP — is the world's largest, making it the standard worked example of the term. That figure is down 7.5% year-on-year and still below its 2010 peak of $1,061.7bn; the 33.911% world-share figure is our own calculation from SIPRI country-level data, not a SIPRI-published total.
At a glance
| US 2025 defense budget | $929.2bnconstant 2024 USD |
|---|---|
| Share of US GDP | 3.12% |
| World rank | #1 |
| Share of world total | 33.911%our calculation from SIPRI country data |
| Year-on-year change | -7.5% |
| 2010 peak | $1,061.7bn |
A defense budget is the amount of money a government plans to spend on its military in a given year. In 2025, the United States allocated $929.2bn to defense — 3.12% of its GDP and the single largest defense budget in the world.
01 What Does "Defense Budget" Mean?
A defense budget is the funding a national government sets aside, typically through an annual appropriations or spending bill, to cover the cost of its armed forces. It's a forward-looking plan — a legislature approves it before the money is spent — which distinguishes it from "military expenditure," the retrospective figure of what a country actually spent, as tracked by researchers such as the Stockholm International Peace Research Institute (SIPRI). In everyday use, and on this site, the two terms are treated as interchangeable ways of describing the same underlying activity: how much a country spends on its military.
02 Defense Budget Definition: What It Includes
The defense budget definition used by SIPRI, and adopted here, covers a broad set of military-related costs, not just weapons purchases:
- Personnel — salaries and pensions for armed forces and defense ministry staff.
- Operations and maintenance — running costs for bases, equipment, and training.
- Procurement — new weapons, vehicles, and equipment.
- Research and development — military R&D funded by the government.
- Infrastructure and construction — military-related building projects.
Figures on this site are expressed in constant 2024 US dollars, which strips out inflation so that budgets from different years can be compared on a like-for-like basis.
03 The US Defense Budget in 2025: A Worked Example
The United States is the clearest real-world illustration of the term. In 2025, its defense budget was $929.2bn, equal to 3.12% of US GDP. That total ranks first among all countries and accounts for 33.911% of world military spending — a share calculated by dividing the US total by the sum of every country SIPRI reports 2025 military expenditure for (a small number of states, such as North Korea, are excluded because SIPRI does not publish estimates for them). See the full 2025 world rankings for how other countries compare.
| Metric | 2025 value |
|---|---|
| Defense budget | $929.2bn |
| Share of GDP | 3.12% |
| World rank | 1 |
| Share of world total | 33.911% |
The world-share figure is our calculation from SIPRI country-level data, not SIPRI's own published total.
04 How the US Defense Budget Has Changed Over Time
A defense budget is not a fixed number — it moves year to year with policy, threat perception, and fiscal conditions. The US figure fell 7.5% between 2024 and 2025, in constant 2024 dollars. Looking further back, the 5-year compound annual growth rate (CAGR) is -0.3%, meaning the budget has been roughly flat to slightly declining over that period, while the 10-year CAGR is 1.03%, a modest long-run increase. The US defense budget peaked in 2010 at $1,061.7bn; the 2025 figure of $929.2bn remains below that high-water mark.
05 Defense Budget vs. Military Expenditure: Is There a Difference?
In technical usage, a "defense budget" is what a legislature approves, while "military expenditure" is what a country actually spends, as measured after the fact by SIPRI. The two figures can diverge — supplemental spending, underspending, or off-budget items can widen the gap — but for the purposes of comparing countries and years, the terms are used interchangeably in public reporting and on this site. When a number is described as a country's defense budget for a given year, it refers to SIPRI's constant-dollar military expenditure estimate for that year.
Figures for 2026 and 2027 in SIPRI-derived datasets are estimates, not final actuals, and should be flagged as such when cited.
Frequently Asked Questions
- What does defense budget mean?
- A defense budget is the amount of money a government plans to spend on its military for a given year. The US 2025 defense budget, for example, was $929.2bn.
- What is the defense budget definition used in this data?
- It covers personnel, operations and maintenance, procurement, R&D, and military infrastructure spending, expressed in constant 2024 US dollars to allow comparison across years.
- How big is the US defense budget in 2025?
- $929.2bn, equal to 3.12% of US GDP and 33.911% of world military spending — the largest single defense budget in the world for 2025.
- Is the US defense budget rising or falling?
- It fell 7.5% year-on-year in 2025. Over 5 years its CAGR is -0.3%, and over 10 years it's 1.03%; the budget remains below its 2010 peak of $1,061.7bn.
defensebudget.org
Defense spending data, sourced from SIPRI
defensebudget.org tracks military expenditure for 160 countries using the SIPRI Military Expenditure Database. Pages are generated from that dataset and reviewed before publication.