The defense budget pays for about 1.3 million active duty troops, hundreds of thousands of reservists and civilians, ships, aircraft, nuclear weapons, bases around the world, and research into future weapons. Its size and priorities shape both national security and the federal budget as a whole.
This guide explains how much the military costs, where the money goes, and how Congress decides.
The Pentagon plans years ahead through its Planning, Programming, Budgeting, and Execution process, a system dating to the 1960s. The services and combatant commands submit needs, the Office of the Secretary of Defense sets priorities, and the Office of Management and Budget folds the request into the President's budget each spring. The request includes a five-year plan, and critics say the long process makes it hard to adopt new technology quickly.
The Armed Services committees write the National Defense Authorization Act, which sets policy, troop levels, and spending limits and has passed for more than 60 straight years. The Appropriations committees write the separate defense appropriations bill that actually provides the money. When Congress misses the October 1 deadline, the Pentagon runs on continuing resolutions that generally bar new programs. In 2025 Congress added roughly $150 billion for shipbuilding, missile defense, munitions, and other priorities through a reconciliation law, bypassing the Senate filibuster.
National defense spending, which includes the Defense Department plus nuclear weapons work at the Energy Department, ran a little under $900 billion a year in the mid-2020s before reconciliation money. That is about 3 percent of the economy, down from more than 9 percent during the Vietnam War and about 6 percent at the height of the Reagan buildup. It accounts for roughly half of the discretionary budget that Congress sets each year, while Social Security, Medicare, and Medicaid make up much larger shares of total spending.
The budget is divided into accounts. Operation and maintenance, the largest, pays for training, fuel, repairs, and civilian salaries. Military personnel covers pay, housing allowances, and benefits. Procurement buys ships, aircraft, vehicles, and munitions, and research, development, test, and evaluation funds new technology. Smaller accounts pay for military construction and family housing. By department, the Navy and Marine Corps, the Air Force and Space Force, and the Army each receive roughly a quarter, with the rest going to defense-wide agencies.
Supporters of higher spending say rising threats from China and Russia, depleted munitions stocks, an aging fleet, and new missile and space threats require major investment, and that defense remains a smaller share of the economy than during most of the Cold War. Critics argue that the Pentagon wastes money, cannot pass an audit, pays too much for weapons that run late and over budget, and that funding through reconciliation avoids normal scrutiny. Fiscal conservatives and progressives have at times joined in calling for cuts, while others debate whether spending targets the right priorities.
In September 2025 an executive order authorized the Defense Department to use the secondary name Department of War, while the legal name set by Congress remained unchanged. In April 2026 the administration requested $1.5 trillion for national defense in fiscal 2027, including $1.15 trillion in the regular budget and $350 billion expected from a new reconciliation bill, the largest request in history. It emphasized the Golden Dome missile defense system, shipbuilding, and munitions.
See the full budget process in how the federal budget works, compare defense with other spending in where your tax dollars go, or see who commands the forces in the military chain of command.