List of countries by past and projected military expenditure (constant US$)

This is a list of countries by past and projected military expenditure in constant US$ exchange rates.

Methodology
Figures for the tables below are provided by the Stockholm International Peace Research Institute data base. They are presented in billions of constant 2011 USD$ exchange rates. Although the database includes statistics for over 150 countries, only countries possessing the largest military expenditures are listed here.

2045
A 2014 academic report from the United Kingdom's Ministry of Defence outlines projected defense expenditure of major powers for the year 2045.