Wars cost money before, during and after they occur — as governments prepare for, wage, and recover from them by replacing equipment, caring for the wounded and repairing the infrastructure destroyed in the fighting. Although it is rare to have a precise accounting of the costs of war — especially of long wars — one can get a sense of the rough scale of the costs by surveying the major categories of spending.
As of August 2016, the US has already appropriated, spent, or taken on obligations to spend more than $3.6 trillion in current dollars on the wars in Iraq, Afghanistan, Pakistan and Syria and on Homeland Security (2001 through fiscal year 2016). To this total should be added the approximately $65 billion in dedicated war spending the Department of Defense and State Department have requested for the next fiscal year, 2017, along with an additional nearly $32 billion requested for the Department of Homeland Security in 2017, and estimated spending on veterans in future years. When those are included, the total US budgetary cost of the wars reaches
$4.79 trillion.