The Scholastic Aptitude Test (SAT) is an exam most universities require of incoming freshman. The score that a student receives on this test significantly influences the likelihood that he/she will become accepted into their school of choice. In addition, the SAT gauges a student's readiness for college level courses. A high score will not only help a student get admitted into the best universities, but it also opens the possibilities for scholarships and financial assistance. There are numerous benefits to mastering the SAT.
The ACT test contains 5 sections (English, Math, Reading, Science and an OPTIONAL Writing Test) as opposed to the SAT which has only 3 sections (Math, Reading, the optional essay, and Writing). Depending on your student's strengths, the ACT may be a better option.
Unless explicitly stated by the school a student wishes to become admitted into, the test a student chooses to take is entirely up to them. I can help narrow down the better option after assessing your high school student's strengths and weaknesses.
I use only officially released tests for tutoring. Diagnostic exams can be administered if students have not taken the tests before so that I may identify areas of weakness and strength.