ACT^® Practice Test

Free ACT Practice Test 2026 | Online ACT Prep

Welcome to the ACT^® practice test page!

Click the “Start Test” button above to begin our free ACT practice test! These ACT practice questions will give you a better idea of what to study for your exam.

ACT Practice Tests by Subject

If you need some extra practice in a specific subject, click one of the subjects below to get started on a subject-specific ACT practice test.

Good luck with your studying!

Test Outline

There are two versions of the ACT test: online and paper-and-pencil. For both versions, the test is split into five sections and the Writing and Science sections are optional.

The ACT contains 171 multiple-choice questions and has a time limit of about 3 hours.

Top 5 Most Challenging ACT Questions

Now that you know more about the test, try your hand at some targeted practice!

Over the last year, we’ve compiled the data from about 5,000 test-takers who tried their hand at the practice test at the top of this page. According to the data, around 70% of people answered these five questions incorrectly.

Answer each question and read through the answer explanation, whether you got the answer right or wrong. This will help you ensure you’ve got the topic mastered.

Whether you struggled with these questions or aced them on your first try, be sure to take the full practice test to get a better idea of how prepared you really are!

1. Read the passage below before answering the question:

Read Passage

Although it’s now been replaced by more advanced techniques, a common apparatus that physicists used in the past to detect cosmic rays and short-lived subatomic particles was a device called a cloud chamber. Cloud chambers were used in the discovery of the positron, the positively charged antimatter version of the electron; the muon, an unstable particle similar to an electron but more massive; and the kaon, an even more massive and shorter-lived particle.

A cloud chamber consists of a sealed container in which the air is supersaturated with water or alcohol vapor. As the high-energy particles and photons pass through the vapor, they ionize the gas particles, leaving a visible trail of droplets that mark the particle’s passing. The characteristics of the trail can give hints to the particle’s nature. More massive particles tend to leave wider tracks; unstable particles can form brief tracks that start where the particle formed (usually by a collision with a cosmic ray) and end where it decayed. Often a magnetic field is applied across the cloud chamber, which further aids in the identification of particles because it causes charged particles to follow a curving path, the direction of the curve depending on the sign of the charge. Even if they have the same charge, faster and more massive particles will tend to curve less than slower or less massive ones.

Below is a diagram of possible paths found in a cloud chamber, with paths and points labeled. The cloud chamber has a magnetic field applied downward (into the page), causing positively charged particles to curve to the left and negatively charged particles to the right.

What is trail 5 most likely to represent?

A.An electron B.A positron C.A cosmic ray D.A kaon Submit

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Hardest Question

Only 27% answered correctly

3. The sides of a triangle are equal to integer values of units. Two sides are 4 and 6 units long, respectively. What is the minimum value for the triangle’s perimeter?

A.10 units B.11 units C.12 units D.13 units Submit

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4. Read the passage below before answering the question:

Read Passage

A student interested in rocketry decides to test the relationship of a rocket’s mass to the peak velocity it can attain, all else being equal. The student reasons that because the impulse provided by the engine does not depend on the rocket’s mass, and because impulse equals mass times change in velocity, the rocket’s peak velocity should be inversely proportional to the rocket’s mass.

To test the hypothesis, the student acquires six identical model rockets. The student outfits each rocket with a sensor to measure its velocity and attaches weights to increase their mass, distributing the weight as evenly as possible. The student fires each rocket, records its peak velocity, and obtains the following data:


After the experiment, the student looks up the expected thrust, impulse, and burn time of the type of rocket used and, with those values, calculates the expected final velocity—which does not match the experimental results. However, reading up further on rocketry after the experiment, the student realizes something that was overlooked in the initial reasoning: the mass of a rocket is not constant but decreases as the fuel is expended.

How would the previous calculations have been off if he used the rockets’ initial mass and did not take into account the change?

A.The calculated velocities would have been too low. B.The calculated velocities would have been too high. C.The calculated velocities would not have been affected by this detail. D.Some of the calculated velocities would have been too low and others too high, depending on the rockets’ masses. Submit

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5. Read the passage below before answering the question:

Read Passage

One of the biggest open questions in cosmology involves a phenomenon called dark matter. Among other lines of evidence, calculations on the motion of the stars in a galaxy seem to show that the mass of the stars, gas, and dust in a galaxy is not sufficient to hold the galaxy together; if there’s no other force constraining it, a galaxy should fly apart as it rotates. Because of this, most cosmologists have concluded that galaxies must contain a large amount of additional mass not accounted for by the structures we have so far been able to detect. This additional matter is known as “dark matter”— “dark” because it apparently cannot be seen or detected by current means. Not all astronomers, however, agree that dark matter is the best explanation for the phenomena in question. Two scientists express their opinions about dark matter.

Scientist 1
Relativistic gravitational theory has passed every experimental test it has been subjected to and has shown considerable explanatory power. It is far too well established to throw out without a good reason to do so. Cosmological observations do not provide such a reason because they have a much simpler potential explanation: the existence of dark matter. Most likely dark matter comprises some yet undiscovered type of elementary particle. Astrophysicists have named several possible candidates, including the weakly interacting massive particle, or WIMP; the gravitino, a particle related to the graviton but with a different spin; or a light, slow-moving particle called an axion.

Scientist 2
Supposing that 85% of galaxies are made up of some unknown and undetectable type of matter is not the most parsimonious way to explain the observations. Current gravitational theories have only been tested on relatively small scales, from a cosmological point of view. We know they work well within the solar system. But it could be that they break down on galactic scales—as Newtonian mechanics works well for objects moving at everyday velocities but fails for objects moving near the speed of light. It seems more likely that the anomalies in large-scale observations come from the fact that gravity simply behaves differently at those scales.

Some recent observations seem to show that at least two galaxies, NGC-1052-DF2 and NGC-1052-DF4, do have enough visible mass to account for their motion and therefore contain little or no dark matter. If these measurements turn out to be valid, on which scientist’s statement would they cast the most doubt?

A.Scientist 1’s because Scientist 1 insists that all galaxies must contain dark matter B.Scientist 1’s because they would prove that gravity does not work the same on larger scales C.Scientist 2’s because Scientist 2 assumes that galaxies must follow Newtonian mechanics D.Scientist 2’s because if gravity works differently at a large scale, this should apply to all galaxies Submit

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ACT Online Prep Course

If you want to be fully prepared, Mometrix offers an online ACT prep course designed to give you everything you need to succeed!

Here’s what you’ll find in the ACT course:

Click below to check it out!

ACT Bubble Sheet (PDF)

When you take the ACT, you’ll fill in your answers using a bubble sheet.

To get the hang of using an ACT test answer sheet, you can download the one below for free!

This printable bubble sheet is designed to help you practice filling out answers just like on test day, so you can boost your confidence and accuracy. Download it now and get one step closer to acing the ACT.

Download Bubble Sheet Download ACT Bubble Sheet PDF

High School Student Toolkit: A Guide to College Success

Get expert tips on acing college applications, preparing for tests, managing finances, and navigating college life. Your guide to success starts here!

How to ACT Prep

Start with an ACT Practice Test

Before creating your study schedule, take an ACT practice test to establish a starting point. You don’t need to wait until you have reviewed every topic. At this stage, the goal is to identify where your preparation time will have the greatest effect.

Review your results by section and content area:

• English: Do you struggle with passage organization, effective transitions, precise wording, sentence structure, grammar, usage, or punctuation?
• Math: Do you need more work with algebra, functions, geometry, statistics, probability, number concepts, or applying several mathematical skills within one problem?
• Reading: Can you identify key ideas and supporting details, interpret words and phrases in context, analyze an author’s choices, and connect information from different parts of a passage?
• Science (optional): Can you interpret graphs and tables, understand experimental procedures, compare scientific explanations, and determine whether evidence supports a conclusion?
• Writing (optional): Can you develop a clear position, engage with multiple perspectives, organize your ideas, support your reasoning, and maintain control of written English?

Identifying those specific weaknesses will show you where to devote more attention during your study time.

Review Difficult Questions

After each practice session, review every question you answered incorrectly AND every question you guessed on or answered with low confidence. Guessing correctly does not necessarily mean that you have mastered the skill.

For each difficult question, determine which of the following caused the problem:

• You did not understand the concept or rule being tested.
• You misread the passage, graph, table, or question.
• You selected an answer that sounded reasonable but was not fully supported.
• You made a calculation or algebra error.
• You used the calculator inefficiently or entered something incorrectly.
• You spent too much time trying to determine the answer.

Then, outline a specific plan for improvement based on what you discovered. In other words, don’t just say, “I need to study English.” Specify that you need to practice sentence boundaries, transitions, modifier placement, or choosing details that support a passage’s purpose.

For science questions, determine whether the difficulty came from reading the data, understanding the experiment, identifying variables, or comparing competing explanations. Do not automatically assume that every missed science question represents a gap in scientific knowledge.

Utilize Answer Explanations

Answer explanations are an underutilized studying resource. To take full advantage of them, read the explanation for every question you found difficult, including questions you answered correctly.

For each one, make sure you can confidently explain:

1. Why the correct answer is correct
2. Why each incorrect option is wrong
3. What skill, rule, or concept the question tests
4. Which information in the question supports the answer
5. How the same skill could appear in a different ACT question

For English questions, identify the exact grammar rule or rhetorical purpose involved. An answer should not be considered correct merely because it sounds more natural.

For math questions, solve the problem again from the beginning without copying the explanation. Then, determine whether another method would be faster. The ACT lets you use an approved calculator, but not every question is best solved with one.

Study Concepts, Not Individual Questions

Memorizing the answer to an ACT practice question will not prepare you for a new question testing the same skill with a different passage, sentence, equation, graph, or experiment. Your goal should be to recognize and apply the underlying skill.

For example, don’t memorize which punctuation mark worked in one sentence. Learn how to identify independent and dependent clauses and determine whether the sentence requires a period, semicolon, comma, colon, or no punctuation.

The exact questions on your test will be different from the ones you encounter during practice. If you can explain a skill without looking at your notes and then apply it correctly to a new question, that is a good indication that you have mastered it.

By Peter Rench

Peter Rench joined Mometrix in 2009 and serves as Vice President of Product Development, responsible for overseeing all new product development and quality improvements. Mr. Rench, a National Merit Scholar, graduated magna cum laude with a Bachelor of Science in Mechanical Engineering and a minor in mathematics from Texas A&M University.

Edited by Aaron Lanni

Aaron is the content manager and lead editor for Mometrix Academy. He regularly produces, updates, proofreads, and edits content to ensure it meets Mometrix’s quality and accessibility standards.

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