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.
1. Aptitude vs. Achievement
The SAT was 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.2. Test Length
The ACT has 215 questions plus the optional essay. The SAT has 140 questions plus the required essay. The actual testing time for the ACT with essay is 3 hours and 25 minutes while the SAT takes 3 hours and 45 minutes (total test time is longer for both because of breaks). Thus, the ACT allows less time per question.3. 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.4. 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.5. 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.6. The SAT Guessing Penalty
The 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. The ACT has no guessing penalty. This difference doesn't really make one exam easier or harder than the other, but some students do find the guessing penalty stressful.7. Essay Differences
The essay on the ACT is optional, although many colleges require it. On the new SAT, the essay is required. You have 25 minutes to write the SAT essay and 30 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. The SAT essay prompts tend to present a broad issue that you need to explore using examples from history, literature or your personal experiences.8. 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.9. 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. Finally, the essay for the SAT comes first; the ACT optional essay is last.10. 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.
11. Further ACT and SAT Score Information
To learn more about SAT and ACT scores, check out these articles:- What's a Good SAT Score?
- What's a Good ACT Score?
- What Colleges Don't Require Test Scores?
- SAT Score Comparison Charts: the Ivy League | top private universities (non-Ivy) | top liberal arts colleges | more top liberal arts colleges | top public universities | top public liberal arts colleges | University of California campuses | Cal State campuses | SUNY campuses
- ACT Score Comparison Charts: the Ivy League | top private universities (non-Ivy) | top liberal arts colleges | more top liberal arts colleges | top public universities | top public liberal arts colleges | University of California campuses | Cal State campuses | SUNY campuses

