Each branch of the military has slightly different requirements to enlist, but all five services dictate that enlistees must be American citizens or resident aliens, be at least 17 years of age, have a high school diploma and be able to pass a basic physical exam. There are also differences in the rules for those wishing to enlist and those seeking entrance into an officer-candidate school. Officer candidate programs are highly competitive, and most require a bachelor’s degree.
While the lower age limit is the same for all branches, the upper limit differs fairly widely. The Air Force has the narrowest range with an upper limit of 27, and the Marines have a similarly low limit of 29. The Army and the Marines set an upper age limit of 34, and the Coast Guard has the widest age range of all five branches with the upper limit for applicants set at 39.
To join the Air Force, the Army or the Coast Guard, an applicant can have no more than two dependents, but the Navy and the Marines have no such restriction.
Applicants to all five branches must pass the Armed Services Vocational Aptitude test. The Air Force and Navy require applicants to score a minimum of 50, while the Coast Guard requires a score of 45. The Marines require a score of 32, while the Army's minimum required score is the lowest at 31.