Methodology

Transparency in how we source, calculate, and present war cost data.

Data Sources

Our analysis draws from the following authoritative sources:

  • Department of Defense (DoD) — Official US defense budget documents, comptroller reports, and cost of war estimates
  • Congressional Budget Office (CBO) — Non-partisan budget analysis, long-term spending projections
  • Congressional Research Service (CRS) — Detailed reports on military operations, aid packages, and defense policy
  • Stockholm International Peace Research Institute (SIPRI) — Global military expenditure database, arms transfers data
  • Brown University Costs of War Project — Comprehensive accounting of post-9/11 war costs including long-term obligations
  • World Bank — Ukraine damage assessments, global economic impact data
  • International Institute for Strategic Studies (IISS) — Military balance data, conflict assessment
  • Kiel Institute for the World Economy — Ukraine Support Tracker (aid tracking from all donor countries)
  • UNHCR — Refugee and displacement statistics
  • Uppsala Conflict Data Program — Armed conflict database

Calculation Methods

Direct Military Costs

We use official budget figures where available (e.g., the DoD budget, congressional aid appropriations). For projected costs (such as a potential Iran conflict), we use analogy-based estimation, scaling from historical conflicts (Iraq, Afghanistan) and adjusting for known differences in military capability, terrain, and strategic complexity.

Per-Taxpayer Calculations

Per-taxpayer figures are calculated by dividing total costs by the number of individual tax returns filed with the IRS (approximately 157 million for the most recent tax year). Per-capita figures use the total US population (approximately 335 million).

Inflation Adjustment

Historical spending figures are adjusted to current-year dollars using the CPI-U (Consumer Price Index for All Urban Consumers) from the Bureau of Labor Statistics. Where noted, some figures use the GDP deflator for broader economic comparisons.

Long-term Cost Projections

Following the methodology established by the Brown University Costs of War Project, our total cost estimates include projected veterans' healthcare and disability costs (using VA actuarial data) and interest on borrowed funds (using CBO's projected interest rate assumptions).

Limitations

  • Classified military spending is not fully captured in public budget documents
  • Some countries (notably China and Russia) do not report military spending transparently
  • Projected costs for hypothetical conflicts involve inherent uncertainty
  • Casualty figures in active conflict zones are often undercounts
  • Economic impact estimates use modeling assumptions that may not capture all variables
  • Data may lag behind real-time events due to official reporting timelines

Updates

We review and update our data regularly as new reports are published. Major annual updates occur when SIPRI releases its global military expenditure data (typically in April), when the US defense budget is enacted, and when significant new aid packages or conflicts materially change our figures.