Hi. I had a question. We recently got back our school-day SAT scores (we take a free SAT at school) and I got a 1500 with not too much studying. Because of this, I am questioning whether or not to retake my ACT because I believe I can get a higher score. In my sophomore year I got a 34C: 34 Reading, 32 Math, 34 Science 34 English. I may want to enter the math department or business and I was wondering if my ACT was too low and if I should retake it and aim for a 35. Thank you 
disclaimer: I AM ASIAN so this also makes it harder.
Like everything, there is a cost/benefit analysis. The cost here being the time spent on test prep that could have been applied to ECs. (And, of course, studying to make sure you get all 'A’s in your classes.) A 1500 SAT is right on the line for what is considered “good enough” for top schools. Trying to get a 35 or 36 ACT may be a good plan, if you really had nothing better to do with the time it would take to achieve that score.
A 34 ACT would be considered a “one & done”. The 1500 SAT is a little trickier to call. If an ivy wants you for other reasons, whether you got a 1500 or a 1600 isn’t going to make a difference. They don’t need a reason to reject you, but if they’re looking for one, they’ll find one, even if you got a 1600. I’d just submit the ACT score and call it a day (unless, of course, you are applying to a school that needs to see all test scores).
Asians have a tougher time at some schools, but a better strategy would be to differentiate yourself through your ECs and essays, because you aren’t going to do so through your test scores.
34 ACT concords to exactly 1500 SAT, and vice-versa, so I don’t see how one can be fine and the other marginal.
Seeing as your composite was a 33.5 rounded up to 34, and no individual score was significantly lower, it will be harder to raise it to 35 than someone with a 35/35/35/32=34C. It sounds like to SAT fits you better - I’d take the SaT over rather than the ACT.
A 34 ACT is a 1520-1550, which is slightly above the OP’s actual SAT score.
https://www.princetonreview.com/college-advice/act-to-sat-conversion
Best to use the ACT/SAT concordance tables.
http://www.act.org/content/dam/act/unsecured/documents/ACT-SAT-Concordance-Information.pdf
https://collegereadiness.collegeboard.org/pdf/guide-2018-act-sat-concordance.pdf
Both say 1490-1520. Equivalent scores. Best to focus on your extracurriculars and subject tests.
(The concordance tables published on both ACT and College Board websites were jointly developed and published in 2018. They are the only current tables. Anything else is old/inaccurate/inapplicable.)