18 years of age (17 years of age with parental consent) for male and female voluntary service; maximum enlistment age 42 (Army), 27 (Air Force), 34 (Navy), 28 (Marines); service obligation 8 years, including 2-5 years active duty (Army), 2 years active (Navy), 4 years active (Air Force, Marines) (2010)
Manpower available for military service:
males age 16-49: 73,145,586
females age 16-49: 71,880,788 (2010 est.)
Manpower fit for military service:
males age 16-49: 60,388,734
females age 16-49: 59,217,809 (2010 est.)
Manpower reaching militarily significant age annually:
male: 2,174,260
female: 2,065,595 (2010 est.)