Each branch of the military sets an AFQT score requirement for applicants. The lowest qualifying score is 31, which is needed to join the Army. Higher scores are required for other branches of the military. For example, the Coast Guard only considers applicants with a score of 40 or more. Prospective recruits who have a GED rather than a high school diploma will, in most cases, need to score at least 50 on the AFQT.
Jobs in the Marine Corps are referred to as”MOS” (short for Military Occupational Specialty). To find the MOSes you qualify for, the Marine Corps organizes your ASVAB subtest scores into various groups known as line scores. The ASVAB subtests are: General Science (GS); Arithmetic Reasoning (AR); Word Knowledge (WK); Paragraph Comprehension (PC); Numerical Operations (NO); Coding Speed (CS); Auto and Shop Information (AS); Mathematics Knowledge (MK); Mechanical Comprehension (MC); Electronics Information (EI); and Sum of Word Knowledge and Paragraph Comprehension (VE). It’s important to remember that as Numerical Operations (NO) and Coding Speed (CS) subtests are phased out, some line scores may be updated.
The ASVAB is a timed test that measures your skills in a number of different areas. You complete questions that reveal your skills in paragraph comprehension, word knowledge, arithmetic reasoning and mathematics knowledge. These are basic skills that you will need as a member of the U.S. military. The score you receive on the ASVAB is factored into your Armed Forces Qualifying Test (AFQT) score. This score is used to figure out whether you qualify to enlist in the armed services.

Including U.S. territories and ships afloat within territorial waters As of 31 December 2009, a total of 1,137,568 personnel were on active duty within the United States and its territories (including 84,461 afloat).[31] The vast majority (941,629 personnel) were stationed at bases within the contiguous United States. There were an additional 37,245 in Hawaii and 20,450 in Alaska while 84,461 were at sea, 2,972 in Guam and 179 in Puerto Rico.

It's important to understand the difference between the ASVAB Standard Scores, and the ASVAB AFQT score. Test takers will receive a separate score for each of the nine sections on the ASVAB. These scores are known as Standard Scores. A Standard Score is used to determine how the test taker compares to the "average" 18-23 year old American on that part of the ASVAB. Not long ago, a large number of people in this age group were given the tests, and these results are the benchmark for Standard Scores. Around half the people in this age group will score a 50 or higher, and about 16% will score a 60 or higher. In other words, the scoring is based on a standard bell curve distribution. Standard Scores are very important when it comes to determining which military job a person will be assigned to.
Jump up ^ Iversen, Amy C.; Fear, Nicola T.; Simonoff, Emily; Hull, Lisa; Horn, Oded; Greenberg, Neil; Hotopf, Matthew; Rona, Roberto; Wessely, Simon (2007-12-01). "Influence of childhood adversity on health among male UK military personnel". The British Journal of Psychiatry. 191 (6): 506–511. doi:10.1192/bjp.bp.107.039818. ISSN 0007-1250. PMID 18055954.

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.