The US Cost of the Afghan War: FY2002-FY2013 - Center for Strategic and International Studies (CSIS) Report
"It is surprisingly difficult to get a meaningful estimate of the total cost of the Afghan conflict, total spending on Afghan forces and total spending on various forms of aid. More data are available on US efforts – which have dominated military and aid spending, but even these data present serious problems in reliability, consistency, and definition. Moreover, it is only since FY2012 that the US provided an integrated request for funding for the war as part of its annual budget request. The data for the period before FY2009 are accurate pictures of the Department of Defense request, but there is only a CRS estimate of total spending the previous years. This report addresses the cost to the US of the Afghan War from FY2000-FY2013. It provides estimates of total cost, cost to the Department of Defense, and aid costs to State, USAID, and other federal agencies. It also reports on the total cost of international aid when this takes the form of integrated aid to Afghan development and Afghan forces – a fraction of total aid spending. No reliable estimate exists of total international aid to Afghanistan, since so much of this aid has been direct and has not passed through the Afghan Central government."