Should I take the SAT Subject Test?

If you're applying to competitive colleges, it's quite possible that many of them will require or recommend at least 2 SAT Subject Tests. For instance, MIT requires 1 math subject test and 1 science subject test (see their testing requirements here: https://mitadmissions.org/apply/firstyear/tests-scores/). You should always check what the schools on your list require, especially as some of them may require specific exams.

Even if a college doesn't require Subject Tests, almost all colleges will consider them, and they're a great way to show strength in a certain domain. So the short answer is yes, regardless of what your schools require, especially if they're competitive - it would be a good idea to take at least 2 Subject Tests!

There's a CollegeVine article that actually outlines which Subject Tests are recommended for different STEM majors: https://blog.collegevine.com/what-sat-iis-should-you-take-for-stem-engineering-majors/

First, you should always do what your school requires or recommends. If they don't specify, it's recommended that you take 1 math subject test, 1 science subject test, and 1 humanities test (selective schools want to see that their students can perform well across disciplines). You mentioned being rusty in the 3 science topics covered by SAT Subject Tests - luckily, you probably don't need to refresh your knowledge in all 3, as you'll likely only need to take 1 of those tests. In this case, you'd definitely want to relearn the material for the science subject that interests you most, and the one you're best at. You could also take a diagnostic practice test for all 3, and see which one you perform best on naturally.

Taking one or more SAT Subject Tests demonstrates your mastery of very specific material (as contrasted to the SAT and ACT, which test a broader knowledge of reading, writing, and math). Therefore, if you've taken a course at a high level (i.e. AP, IB, Dual Enrollment, or maybe even Honors) and have been successful in that respective course, consider taking an SAT Subject Test in that subject area. Most top schools recommend at least 2 SAT Subject Tests, and some (like MIT) have specific guidelines regarding SAT Subject Tests. Make sure to visit each university's website for more specific information.

Now, because you are interested in going into science, I would recommend at least 1 SAT Subject Test in either biology, chemistry, or physics. A second or third one can be in science, math, or it could even be in a humanities or language area. However, make sure that at least 1 test is related to what you want to pursue in college.

Therefore, if you have taken a course in biology, chemistry, or physics, review the content and devote time to studying for the test. Many companies make SAT Subject Test prep books, and there is practice online as well. With a strong understanding of the material and adequate review and preparation, you should be ready for any such test. All the best!