Military of United States
| Military branches: | Army, Navy and Marine Corps, Air Force, and Coast Guard; note - Coast Guard administered in peacetime by the Department of Homeland Security, but in wartime reports to the Department of the Navy |
| Military service age and obligation: | 18 years of age; 17 years of age with written parental consent (2006) |
| Manpower available for military service: | males age 18-49: 67,742,879 females age 18-49: 67,070,144 (2005 est.) |
| Manpower fit for military service: | males age 18-49: 54,609,050 females age 18-49: 54,696,706 (2005 est.) |
| Manpower reaching military service age annually: | males age 18-49: 2,143,873 females age 18-49: 2,036,201 (2005 est.) |
| Military expenditures - percent of GDP: | 4.06% (2005 est.) |