Differences Between the SAT and ACT Exams

Figure Out if the SAT or ACT is the Right Exam for You

What are the differences between the SAT and ACT exams? Should you take just one of the tests or both of them?

Most colleges accept SAT or ACT scores, so you may wonder if you should take the SAT, ACT or both exams. It's even possible you won't need either exam given the growing number of test-optional colleges. On the flip side, you may find that if you take the ACT, you still need to take SAT subject tests. A 2015 Kaplan survey found that 43% of college applicants take both the SAT and the ACT.

Many students score similarly on the ACT and SAT. However, the tests do assess different information and problem solving skills, so it's not unusual to do better on one exam than the other. Key exam differences are outlined below. Princeton Review's book ACT or SAT? may also be of use.

Starting on March 5th, 2016, the College Board launched a major revision of the SAT exam. Those changes are now reflected in the comparison below.

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Aptitude vs. Achievement

The SAT was originally designed as an aptitude test -- it tests your reasoning and verbal abilities, not what you've learned in school. In fact, the SAT was supposed to be a test that one could not study for -- studying does not change one's aptitude. The ACT, on the other hand, is an achievement test. It is meant to test what you have learned in school. However, this distinction between "aptitude" and "achievement" is dubious. There's concrete evidence showing that you can study for the SAT, and as the tests have evolved, they have come to look more and more like each other. The new SAT exam launched in 2016 is much more of an achievement exam than earlier versions of the SAT.

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Test Length

The ACT has 215 questions plus the optional essay. The new SAT has 154 questions plus a (newly) optional essay. The actual testing time for the ACT without essay is 2 hours and 55 minutes while the SAT takes 3 hours--with an added 50 minutes if you choose to write the optional essay (total test time is longer for both because of breaks). So, while the SAT takes a little bit longer, it allows students more time per question than the ACT.

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ACT Science

One of the biggest differences between the ACT and SAT is that the ACT has a science test that includes questions in areas such as biology, chemistry, physics and earth science . However, you don't need to be a science whiz to do well on the ACT. In fact, the science test is really assessing your ability to read and understand graphs, scientific hypotheses, and research summaries. Students who do well with critical reading often do well on the Science Reasoning Test.

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Writing Skills Differences

Grammar is important for both the SAT and ACT, so students taking either exam should know rules for subject/verb agreement, proper pronoun usage, identifying run-ons and so on. However, the emphasis in each exam is a little different. The ACT places more emphasis on punctuation (learn those comma rules!), and it also includes questions on rhetoric strategies.

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ACT Trigonometry

The ACT has a few questions that require trigonometry. The SAT does not. ACT trig is quite basic, but you should go into the exam understanding how to use sine and cosine.

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The SAT Guessing Penalty

The old SAT was designed so that random guessing hurts your overall score. If you can eliminate at least one answer, you should guess, but otherwise you should leave the answer blank. This has changed, as of March 2016: there is now no guessing penalty for the SAT. This was a confusing aspect of the test for many students; now, it is better to guess at an answer (after eliminating all wrong answers) than to leave the question blank. 

The ACT has never had a guessing penalty. 

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Essay Differences

The essay on the ACT is optional, although many colleges require it. Until recently, the SAT essay was required. Now, it is optional again. If you choose to write the essay for either test, you have 50 minutes to write the SAT essay and 40 minutes to write the ACT essay. The ACT, more than the SAT, asks you to take a stand on a potentially controversial issue and address the counter-argument as part of you essay. For the new SAT essay prompt, students will read a passage and then use close-reading skills to explain how the author builds his or her argument. The essay prompt will be the same on all exams--only the passage will change.

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SAT Vocabulary

The SAT critical reading sections place more emphasis on vocabulary than the ACT English sections. If you have good language skills but a not-so-great vocabulary, the ACT might be the better exam for you. Unlike students who take the SAT, ACT exam takers won't improve their scores significantly by memorizing words. However, with the recent redesign of the SAT, students will be tested on more commonly used vocabulary words, not on extremely rare ones (think obstinate instead of pertinacious).

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Structural Differences

Students taking the SAT will find that the questions get more difficult as they progress. The ACT has a more constant level of difficulty. Also, the ACT math section is all multiple choice whereas the SAT math section has some questions that require written answers. For both tests, the optional essay is at the end.

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Scoring Differences

The scoring scales for the two exams are quite different: each section of the ACT is out of 36 points, whereas each section of the SAT is out of 800 points. This difference doesn't matter much since scores are weighted so that it's equally hard to get a perfect score on either exam, and average scores are frequently around 500 for the SAT and 21 for the ACT.

One significant difference is that the ACT provides a composite score -- it shows how your combined scores measure up against other test takers. The SAT provides just individual scores for each section. For the ACT, colleges often place more weight on the composite score than individual scores.