To enter the military, you must earn ASVAB scores that compare favorably to the normal scores achieved by other test-takers between the ages of 18 and 23. Specifically, the military looks at your scores on the Arithmetic Reasoning, Math Knowledge, and Verbal Composite (Word Knowledge and Paragraph Comprehension) subtests. This set of tests is called the Armed Forces Qualifying Test (AFQT) and is considered a good assessment of general knowledge and skills. The ASVAB scores you receive in these areas must exceed the minimum requirements for the branch of service you wish to enter. These minimum scores vary for the different branches.
At present, the minimum required ASVAB scores on the AFQT are as follows, in descending order: Coast Guard (36); Air Force (36); Navy (35); Marines (32); and Army (31). These minimum score requirements are subject to change without warning, however. In addition, within each branch there are certain minimum score requirements for various specialties. An aspiring serviceman or servicewoman who wants to work in military public relations, for instance, will need higher Verbal scores than one who is hoping to work with heavy machinery. Once you have taken the exam, your ASVAB scores remain valid for two years.