In the Navy, the rank of Admiral of the Navy theoretically corresponds to that of General of the Armies, though it was never held by active-duty officers at the same time as persons who held the rank of Fleet Admiral. George Dewey is the only person to have ever held this rank. After the establishment of the rank of Fleet Admiral in 1944, the Department of the Navy specified that the rank of Fleet Admiral was to be junior to the rank of Admiral of the Navy. However, since Dewey died in 1917 before the establishment of the rank of Fleet Admiral, the six-star rank has not been totally confirmed.

Since 1976, the multiple-choice ASVAB has been used for initial aptitude screening as well as MOS classification. The exam has changed since its inception. While some parts have remained, such as arithmetic reasoning and word knowledge, others like tool knowledge have been removed in favor of questions related to assembling objects. After nearly 20 years of research and development, a computer-adaptive version of the exam was implemented in 1996. The CAT-ASVAB is the first large-scale adaptive battery test to be administered in high-stakes environments like a Military Entrance Processing Station. The paper and pencil, or P&P version is still used at a variety of other military testing sites.
The projected active duty end strength in the armed forces for fiscal year 2017 was 1,281,900 servicemembers,[6] with an additional 801,200 people in the seven reserve components.[6] It is an all-volunteer military, but conscription through the Selective Service System can be enacted at the President's request and Congress' approval. All males ages 18 through 25 who are living in the United States are required to register with the Selective Service for a potential future draft.

The process of allocating resources is conducted by determining a military budget, which is administered by a military finance organisation within the military. Military procurement is then authorised to purchase or contract provision of goods and services to the military, whether in peacetime at a permanent base, or in a combat zone from local population.

Prospective service members are often recruited from high school or college, the target age ranges being 18–35 in the Army, 18–28 in the Marine Corps, 18–34 in the Navy, 18–39 in the Air Force and 18–27 (up to age 32 if qualified for attending guaranteed "A" school) in the Coast Guard. With the permission of a parent or guardian, applicants can enlist at age 17 and participate in the Delayed Entry Program (DEP), in which the applicant is given the opportunity to participate in locally sponsored military activities, which can range from sports to competitions led by recruiters or other military liaisons (each recruiting station's DEP varies).
The vast majority of ASVAB test takers will ultimately not enlist in the military. The ASVAB Career Exploration Program claims that only two-and-a-half percent of those who participate in the ASVAB join the military. Forty-seven percent of those who take the exam indicate an interest in attending a four-year college, and 16 percent of those who take the exam originally indicate some kind of an interest in joining the military.
The Armed Forces Qualification Test (AFQT) is used by all of the Services to determine if an applicant is eligible for the military. Four of the ASVAB subtests are combined to form the AFQT. It measures general cognitive ability and is composed of verbal and mathematics subtests. AFQT scores are grouped into categories for reporting purposes. The table below shows the AFQT categories and the percentile score ranges corresponding to the categories. Applicants that score in AFQT category IIIA or higher may qualify for enlistment incentives.