You can take the test as a junior or senior in high school and use the score to enlist, provided that you are at least 17 years old and took the test no earlier than 2 years before you begin enlistment processing. If you are at least 17, you can take the test at a Military Processing Station (MEP) or a satellite Military Entrance Test (MET) location.
If you’re planning on using your scores for military enlistment, you may be hoping to achieve a score that is high enough for a specific signing bonus. While it’s natural to want to do your best, putting extra pressure on yourself can cause unnecessary anxiety. Take a few deep breaths, relax, and remember that taking the test is only part of the entire recruitment process.

In order to take the ASVAB at a MEPS for enlistment purposes, an individual will need to speak with a recruiter and schedule a time to take the test. ASVAB testing at a MEPS is self-paced and taken on a computer, and it may be retaken after a one-month waiting period.  Entitled the CAT-ASVAB, the test is adaptive – meaning it adapts to your ability level.
The underlying model used for the ASVAB is a three-parameter logistic (3PL) model. This model represents the probability that an examinee at a given level of ability will respond correctly to an individual item with given characteristics. The characteristics used are difficulty, discrimination and guessing (this refers to the likelihood that a very low ability examinee would respond correctly simply by guessing).
The Armed Services Vocational Aptitude Battery is the most widely used multiple-aptitude test battery in the world. As an aptitude test, the ASVAB measures your strengths, weaknesses, and potential for future success. The ASVAB also provides you with career information for various civilian and military occupations and is an indicator for success in future endeavors whether you choose to go to college, vocational school, or a military career.

There are nine sections on the exam: General Science, Arithmetic Reasoning, Word Knowledge, Paragraph Comprehension, Mathematics Knowledge, Electronics Information, Automotive and Shop Information, Mechanical Comprehension, Assembling Objects, and Verbal Expression. The time limits for each section range from 10 – 36 minutes; the entire exam takes three hours.
Focusing Your Study - As you take more and more sample tests you begin to get a feel for the topics that you know well and the areas that you are weak on.  Many students waste a lot of valuable study time by reviewing material that they are good at (often because it is easier or makes them feel better).  The most effective way to study is to concentrate on the areas that you need help on.

You often hear people say something like, "I got a 70 on the ASVAB." What they are talking about is the ASVAB AFQT score or Armed Forces Qualification Test Score. Many people think the AFQT score is the overall ASVAB score, but that's not correct. In fact, the AFQT score is derived from only four of the nine ASVAB subtests: Paragraph Comprehension (PC), Word Knowledge (WK), Mathematics Knowlege (MK), and Arithmetic Reasoning (AR).
Personnel may be posted to bases in their home country or overseas, according to operational need, and may be deployed from those bases on exercises or operations anywhere in the world. During peacetime, when military personnel are generally stationed in garrisons or other permanent military facilities, they mostly conduct administrative tasks, training and education activities, technology maintenance, and recruitment.
Arithmetic Reasoning tests the ability to solve basic arithmetic problems encountered in everyday life. One-step and multistep word problems require addition, subtraction, multiplication, division and choosing the correct order of operations when more than one step is necessary. The items include operations with whole numbers, operations with rational numbers, ratio and proportion, interest, percentage and measurement. Arithmetic Reasoning is one factor that helps characterize mathematics comprehension, and it also assesses logical thinking.
The ASVAB is routinely reviewed to eliminate any potential biases from questions and scoring. The exam underwent a major revision in 2002. Two years later, a renormalization of the percentile scoring system was performed to ensure that a 50 percent score represented performing better than 50 percent of all test takers. The 10-section ASVAB improves the matching of volunteers with available jobs and helps match job openings with qualified individuals.
The remaining six sections on the ASVAB are used to drill down and determine what job you are best suited for in the military as these scores will provide in-depth insight into your knowledge, skills and interests. These six sections are: General Science (GS), Mechanical Comprehension (MC), Electronics Information (EI), and Assembling Objects (AO), Auto Information (AI) & Shop Information (SI). Please note: AI and SI are combined into one single score (labeled AS) on the paper and pencil test.

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.