<p>I don’t know of any schools that require both. Most students will either submit ACT or SAT, however some do submit both. It won’t affect your admission decision.</p>
<p>Generally one or the other test is required by all US colleges for admission, either the SAT or the ACT. Some schools will accept ACT results in place of SAT and subject test results. Others will accept either ACT or SAT but require subject tests of all applicants. Many schools do not require subject tests at all.</p>
<p>Many students in the US take both the SAT and ACT, often more than once. Students tend to improve when they retake a test and many students perform much better on one of the tests than on the other. Many colleges “superscore” the SAT, meaning they’ll consider the highest subscores on each part of the test even if those scores are from different test dates. Some schools superscore the ACT, but that is far less common. </p>
<p>The ACT is offered with and without a separate writing portion and some schools which accept the ACT in lieu of the SAT require applicants to take the ACT with writing.</p>
<p>Most international applicants take only the SAT and often only once, because of cost and distance to testing centers. </p>
<p>You can look at the website of each school where you plan to apply to see its particular testing requirements.</p>