The Cost of War

War is the most expensive activity a nation can undertake. It consumes wealth, destroys infrastructure, kills the young, and burdens the future with debt and trauma. The United States has been at war for roughly 229 of its 249 years of existence — and the costs, both financial and human, are staggering beyond comprehension.

The $8 Trillion War on Terror

According to the Brown University Costs of War Project — the most comprehensive accounting of post-9/11 war spending — the total cost of the War on Terror through 2023 exceeds $8 trillion. This figure includes:

• Direct war-fighting costs in Iraq, Afghanistan, Syria, and elsewhere: $2.9 trillion
• DOD base budget increases attributable to the wars: $1.1 trillion
• Veterans' medical and disability costs: $580+ billion to date (projected $2.2T+ through 2050)
• Interest on war borrowing: $1.1+ trillion
• Homeland Security: $1.2+ trillion since 2001
• State Department war-related costs: $200+ billion

These numbers are updated regularly by the Costs of War Project and continue to grow. The $8 trillion figure does not include the $2.5 trillion in projected future veteran care costs that will accrue through 2050 and beyond. When these are included, the total cost of the War on Terror will likely exceed $10 trillion.

The Brown University Methodology

The Costs of War Project at Brown University's Watson Institute is the gold standard for war cost accounting. Unlike Pentagon estimates (which exclude most long-term costs), the Brown methodology captures:

• Direct budgetary costs: Appropriations for war operations (OCO funding, supplementals)
• Future obligations: Veteran care costs that will accrue for decades (peak costs projected in 2040s)
• Interest costs: Because wars are financed through borrowing, not taxation, interest compounds
• Base budget increases: Permanent DOD spending growth justified by the wars that never reverses
• Related spending: Homeland Security, State Department programs created or expanded by 9/11
• Opportunity costs: Economic activity forgone because resources went to war instead

The Costs of War methodology reveals that the direct fighting costs are only about 36% of total war costs. The rest — veteran care, interest, homeland security, base budget growth — represent the hidden iceberg beneath the surface that politicians rarely discuss. This is why Pentagon cost estimates are systematically misleading: they show only the tip of the iceberg.

Cost Per Taxpayer, Per Household

There are approximately 113 million US taxpayers and 131 million households. Here's what the wars cost each family:

These wars were not funded by taxes — they were funded by debt. The 2001 and 2003 tax cuts actually reduced federal revenue during wartime, a historically unprecedented decision. During World War II, the top marginal tax rate was 94%. During Korea, 92%. During Vietnam, 70%. During the War on Terror: 35% (and falling). The result: every dollar spent on the War on Terror was borrowed, and American taxpayers will be paying interest on that borrowing for generations.

“The United States has fought its post-9/11 wars almost entirely on borrowed money, with the costs shifted to future generations. This is the first time in American history that taxes were cut during wartime.”
— Neta Crawford, Costs of War Project, Brown University

War Costs Across American History

All figures are inflation-adjusted to 2024 dollars for comparison. Note the dramatic trend: modern wars cost exponentially more in dollars but kill fewer Americans — because the killing is increasingly done to others. The cost per American death has risen from $96,000 in the Revolutionary War to over $1 billion in the War on Terror.

The trend is unmistakable: wars are becoming more expensive in absolute terms while killing fewer Americans — because the killing is increasingly done to others. The Iraq War cost $2.4 trillion and killed 4,599 American soldiers. It also killed an estimated 200,000–300,000 Iraqi civilians. The cost per American soldier killed: approximately $522 million. The cost per Iraqi civilian killed: roughly $10,000. The disparity reveals who bears the true burden of American wars.

The Hidden Costs

The costs listed in the table above are the direct costs of each war. The true costs extend far beyond what any budget line item captures:

The Compounding Effect of War Debt

Because the War on Terror was financed entirely through borrowing, the interest costs compound over time. This is perhaps the most insidious hidden cost of all — it grows automatically, requires no new legislation, and will burden taxpayers for generations:

To understand the compounding effect: for every $1 spent on the war itself, American taxpayers will eventually pay approximately $1.40–1.60 once interest is included. By 2050, cumulative interest on War on Terror borrowing alone could exceed $3 trillion. The wars are still being fought — on the balance sheet — long after the troops come home.

Generational Cost Transfer: Who Pays?

The decision to finance wars through debt rather than taxes creates a profound intergenerational injustice. The people who decided to wage these wars and the people who will pay for them are increasingly different groups:

This is the libertarian nightmare scenario: a government waging wars that the population didn't vote for, funded by debt that future citizens didn't consent to, creating obligations that will persist for decades. The 2001 AUMF was passed when Gen Z was in diapers. They will be paying for it into retirement. This is taxation without representation across time.

Per-Conflict Cost Breakdown

Afghanistan: $2.3 Trillion for Nothing

The Afghanistan War (2001–2021) cost approximately $2.3 trillion — or about $300 million per day for 20 years. This includes:

• Direct DOD war-fighting costs: $933 billion
• State Department/USAID reconstruction: $145 billion
• Interest on borrowing: $530 billion
• Veteran care (to date): $296 billion (projected $1T+ through 2050)
• DOD base budget increases: $443 billion

After spending $2.3 trillion, losing 2,461 American lives, and 20 years of occupation, the Taliban — the same group the US went to war to remove — controls Afghanistan again. The Afghan government the US spent hundreds of billions building collapsed in 11 days. The reconstruction funds were largely wasted: the Special Inspector General for Afghanistan Reconstruction (SIGAR) documented billions in fraud, waste, and abuse, including a $43 million gas station, a $28 million “forest” in a desert, and military uniforms in the wrong camouflage pattern that cost $28 million.

Iraq: $2.4 Trillion and Counting

The Iraq War (2003–2011, with ongoing costs) has cost approximately $2.4 trillion, making it the second most expensive war in US history after World War II. Before the invasion, the Bush administration estimated the war would cost $50–60 billion. Economic advisor Lawrence Lindsey was fired for suggesting it might cost $100–200 billion. The actual cost was 40 times the original estimate.

• Direct war-fighting: $839 billion
• Veteran care (to date): $344 billion
• Interest on borrowing: $615 billion
• State Department/reconstruction: $76 billion
• DOD base budget increases: $533 billion

The Iraq War was fought based on intelligence that Iraq possessed weapons of mass destruction. No WMDs were found. An estimated 200,000–300,000 Iraqi civilians were killed. The invasion destabilized the entire Middle East, created the conditions for ISIS, triggered a refugee crisis that destabilized Europe, and empowered Iran as a regional power. It is widely regarded as the worst foreign policy blunder in modern American history.

Vietnam: The Original Forever War

The Vietnam War cost $843 billion in 2024 dollars over 20 years (1955–1975). 58,220 Americans were killed and an estimated 2 million Vietnamese civilians died. The US dropped more bombs on Vietnam, Laos, and Cambodia than all sides in World War II combined. Laos remains the most heavily bombed country per capita in history — unexploded ordnance still kills 50+ people per year.

The parallels to the War on Terror are striking: gradual escalation, presidential deception (Pentagon Papers, Gulf of Tonkin), unfulfillable promises of progress, and an ignominious exit after decades of bloodshed and treasure spent. The lesson of Vietnam — that military force cannot impose political outcomes on unwilling populations — was apparently not learned.

The True Cost Goes Beyond Dollars

War costs don't end when the fighting stops. The US will spend an estimated $2.5T on veteran care through 2050.17 veterans take their own lives every day — over 6,000 per year, more than 130,000 since 2001. 38 million people have been displaced by the War on Terror alone. Entire nations have been destabilized. Generations of children have grown up in war zones.

The environmental costs are similarly staggering. The Pentagon is the single largest institutional consumer of fossil fuels in the world. Its carbon footprint exceeds that of 55countries. Military bases across the US are contaminated with PFAS “forever chemicals” that have entered groundwater supplies. Depleted uranium from munitions has contaminated soil in Iraq and the Balkans. Burn pits in Afghanistan and Iraq exposed hundreds of thousands of troops to toxic fumes, leading to the PACT Act and billions in new healthcare costs.

Opportunity Cost: What Else $8 Trillion Could Have Done

Every dollar spent on war is a dollar not spent on something else. The $8 trillion War on Terror could have:

• Made all public universities free for 100 years ($79B/year)
• Funded universal healthcare for 26 years ($300B/year net new cost)
• Ended homelessness 400 times over ($20B one-time)
• Provided every American household with $61,000
• Rebuilt every bridge, road, water system, and school in America
• Funded a $1 trillion sovereign wealth fund that would generate $50B+ annually forever

Instead, the US spent it on wars that destabilized the Middle East, created ISIS, killed hundreds of thousands of civilians, displaced 38 million people, and left the Taliban in charge of Afghanistan. The opportunity cost of empire is measured not just in what was lost, but in what was never built.

“War is the health of the State.”
— Randolph Bourne, 1918

“It is well that war is so terrible, otherwise we should grow too fond of it.”
— Robert E. Lee, 1862

“I spent 33 years in the Marines. Most of my time being a high-class muscle man for Big Business, for Wall Street and for the bankers. In short, I was a racketeer for capitalism.”
— Major General Smedley Butler, USMC, 1935

Explore More

• War Clock — Watch spending tick in real time
• The War on Terror — The $8 trillion war with no exit strategy
• Cost Per Life — How much each death costs
• Tax Receipt — Your personal military tax bill
• Cost Calculator — Your lifetime war cost
• All Conflicts — Browse all 36 major wars
• Opportunity Cost — What war money could buy instead
• Veteran Suicide — The human cost that never ends