Most U.S. college require you take either the SAT or the ACT examination to apply. What’s the difference between the two? Northjersey.com has a succinct explanation of some of the major differences:
The SAT is considered a reasoning-based test, requiring critical thinking and problem-solving. … The ACT is a curriculum-based test, and strong students may find they do better on the ACT, which is more closely aligned with what they have learned in school.
The pacing is also different on the two exams. The ACT has fewer sections, but each one is longer.
Make sure you also check out the growing list of schools will allow you to apply without having taken either exam.