http://en.wikipedia.org/wiki/ACT_%28examination%29#Format

http://en.wikipedia.org/wiki/SAT#Structure College Board will tell you more specifically what’s on the SAT: http://www.collegeboard.com/student/testing/sat/about/sat/math.html , and www.act.org is for the ACT.

The major difference between the two is that the SAT is an “aptitude” test, and the ACT is an “achievement” test (in theory) — the SAT focuses more heavily on reasoning and critical thinking skills, testing your ability to analyze and solve problems; the ACT (using the way Wikipedia puts it) tests “general educational development”. Where the SAT is purely math and English (reading, writing, vocab), the ACT to a certain extent tests actual knowledge– you’ll need a good basis in basic science concepts for the Science reasoning section, the reading seems to be a test of reading speed more than anything, and the English is straight grammar testing, with maybe a little bit of vocabulary thrown in and the occasional analysis question. The math problems on the ACT are more straightforward than those on the SAT, but they cover about the same areas in math, I think.