SAT or ACT or both

I am a student in the class of 2022 (Junior this year) who is trying to decide whether to take the ACT, SAT, or both. I am planning on going into some sort of S.T.E.M. field with biochemistry being my primary interest as of now. Additionally, would it be best to take these in the Spring or Summer? Thank you in advance!

I would take practice exams of both tests and see if you do better/prefer one over the other.

My son’s guidance counselor (who is excellent) said in her experience 1/3 of students do better on the SAT, 1/3 do better on the ACT, and 1/3 do the same on both.

I would check to see how readily available each test has been in your state. The SAT was canceled every session since the pandemic in our state while the ACT was able to be administered once.

I would expand on what @happy1 said: not just take two practice tests; spend some time studying, on your own or with some help, for each of them. From the experience of a group of kids we know, 1/3 find the ACT more coachable, 1/3 find the SAT more coachable, and 1/3 think they are about the same in that regard.