10 Differences Between the SAT and ACT Exams

Which is the Right Exam for You?

Young man taking an exam, close up photograph.

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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. 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 percent of college applicants take both the SAT and the ACT.

Many students earn a similar percentile ranking 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. There are some key exam differences between the two.

01
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ACT and SAT, Achievement or Aptitude Tests?

The SAT was originally designed as an aptitude test. It tests your reasoning and verbal abilities, not necessarily what you've learned in school. The SAT was supposed to be a test that one could not study for because 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. As the two tests have evolved, they have come to look more like each other. The new SAT exam, launched in 2016, is much more of an achievement exam than the earlier versions of the SAT.

02
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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 the 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. The 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.

03
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ACT Science

One of the biggest differences between the two tests is the science section on the ACT. It 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. The science test is 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.

04
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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-on sentences, and so on. However, the emphasis of each exam is a little different. The ACT places more emphasis on punctuation and includes questions on rhetoric strategies.

05
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ACT Trigonometry

The ACT has a few questions that require trigonometry, while the SAT does not. ACT trig is quite basic. 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. 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. 

07
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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 your 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.

08
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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 a 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).

09
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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.

10
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Scoring Differences

The scoring scales for the two exams are quite different. Each section of the ACT is worth 36 points, whereas each section of the SAT is 800 points. This difference doesn't matter much. Scores are weighted so that it's equally hard to get a perfect score on either exam. 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 that shows how your combined scores measure up against other test-takers. The SAT provides individual scores for each section. For the ACT, colleges often place more weight on the composite score than on individual scores.

Source

"Kaplan Test Prep Survey: Among Parents of College Applicants, 43% Say Their Child is Taking Both the SAT and the ACT." Kaplan, Inc., The Graham Holdings Company, November 5, 2015, New York, NY.