Plan to take the GRE about a year prior to your expected entrance into Graduate School—preferably during the summer or early fall. The deadline for taking the GRE will vary depending on the admission procedures of each school to which you apply, the specific program, and the term in which you plan to enroll. You should consult the application guidelines to find out whether you are required to take a Subject Test in addition to the General Test. These subject tests are only offered three times a year (at a maximum), so factor their schedule into your timeline.
While you can take the GRE up to 5 times, you may only take it once per calendar month (including a month in which you cancel your score). You'll want to schedule enough time in your planning process to register and re-take the test (if necessary) and have a new score submitted to schools before the application deadline. If you are dissatisfied with your initial score, you should retake the GRE only if you are confident that your score will increase considerably—for instance if you were ill or had family/personal problems. Both scores will be reported to the schools in which you apply. Schools typically accept your highest score.
If you take the GRE early, you will have in hand your score and can use it to plan your application strategy and choose schools for which which you will be competitive. Don't forget to choose a “safe” school as well as schools that are more of a long-shot. If you take the GRE early enough, it will allow you to submit your official score along with your application.
If a school uses a rolling admissions process, you will want to make sure your application is in early (usually between December and February depending on the school). Rolling admissions mean that applications are reviewed on a first come, first served basis, and some schools may fill their classes before their final deadlines.
At a minimum, plan to take the GRE six weeks before the application deadline. Because the Analytical Writing Measure is scored separately from the rest of the test, allow roughly 10–15 days for your official score report to be released.
Scores for Subject Tests, which are given in paper and pencil format, are usually reported about six weeks after you take the test. You can arrange for your test score to be sent directly to you and up to 4 schools to which you are applying. Be aware that some universities have chosen to receive GRE scores in a format that is distributed a couple of times a month—a further delay that should be considered when planning a date to take the test.
Because the GRE General Test is a Computer-Based Test, you can take the exam at almost any time. Each test center has its own schedule of operation, but available time slots can fill quickly (especially on weekends). In some cases, it may be possible to schedule an appointment a day or two in advance, but don't count on it. We recommend booking a time and date at least a month in advance (two months isn't a bad idea if you have limited availability or are taking it during the busy time between November and January). You may visit www.gre.org for a list of test center locations and to register online.
If you need to take a GRE Subject Test, make sure you schedule this test at least 6 weeks in advance. As noted, ETS offers these tests a maximum of three times a year.