As a general rule of thumb, anything over an 85 on the ASVAB will qualify you for nearly any position in the armed forces. But there are slight breakdowns within each score. For example, in order to qualify for Surveillance and Communications (SC) in the Army, Word Knowledge, Paragraph Comprehension, Arithmetic Reasoning, Auto & Shop and Mechanical Comprehension all require high marks. Though scoring an 85 or above would guarantee you scored in a high enough percentile to qualify for SC.
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.
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.
One ASVAB sub-measure, the Armed Forces Qualification Test (AFQT)--which is just a separate analysis of the same tests that focuses only on four of the subtests--is also population-referenced, but its score from 1-99 is a percentile score. This means that if you score a 73, you scored as well as or higher than 73% of test-takers in the national sample.