A previous CBO estimate put the wars' costs at more than $1.6 trillion. This one adds $705 billion in interest, taking into account that the conflicts are being funded with borrowed money.
"The number is so big, it boggles the mind," said Rep. Rahm Emanuel, D-Ill.
The CBO estimates assume that 75,000 troops will remain in both countries through 2017, including roughly 50,000 in Iraq. That is a "very speculative" projection, though it's not entirely unreasonable, said Loren Thompson, a defense analyst at the non-partisan Lexington Institute.
As of Sept. 30, the two wars have cost $604 billion, the CBO says. Adjusted for inflation, that is higher than the costs of the Korea and Vietnam conflicts, according to the Washington-based Center for Strategic and Budgetary Assessments.