Neta Crawford of Boston University, the author of the report, included interest on borrowing, future veterans needs, and the cost of homeland security in her calculations.

The amount of $4.79 trillion, "so large as to be almost incomprehensible," she writes, adds up like this:

The wars in Iraq, Afghanistan, Pakistan, Syria, and other overseas operations already cost $1.7 trillion between 2001 and August 2016 with $103 billion more requested for 2017

Homeland Security terrorism prevention costs from 2001 to 2016 were $548 billion.

The estimated DOD base budget was $733 billion and veterans spending was $213 billion.

Interest incurred on borrowing for wars was $453 billion.

Estimated future costs for veterans' medical needs until the year 2053 is $1 trillion.

And the amounts the DOD, State Department, and Homeland Security have requested for 2017 ($103 billion).