How is the ACT Science section structured, why is it now optional, and what does that mean for your test plan?
The ACT Science format: 40 questions built from short passages with figures, now an optional section on the enhanced ACT that feeds the STEM score but not the Composite, with a legacy 35-minute form offered through late 2025.
A focused answer on how the ACT Science section is structured and why it is now optional: 40 questions from short scientific passages with figures, 40 minutes on the enhanced ACT (35 on the legacy form), scored 1 to 36, feeding the STEM score but no longer the Composite, and what that change means for your plan.
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What this topic is asking
Before you read a single graph, you need an accurate model of what the ACT Science section is now, because the test changed in 2025 and a lot of older advice is out of date. The headline change is that Science became an optional section on the enhanced ACT. The structure of the section, what it tests, and how it is scored all flow from that one fact, and getting it right shapes your whole test plan.
The structure of the section
ACT Science is a set of short passages, each followed by a group of questions, adding up to 40 questions in total. Almost every passage comes with one or more figures: a line graph, a bar chart, a data table, a diagram, or a combination of them. A small introduction sets the scene, and then the questions send you back into the figures and text for the answers.
The questions are not ordered strictly from easy to hard, the way some sections are. Difficulty varies passage by passage and question by question, which is why choosing the order you attack the passages is its own skill, covered in ordering the passages.
Why the section is now optional
In 2025, ACT, Inc. introduced the enhanced ACT. Two sections became optional: the long-standing optional Writing test, and now Science. The core of the test - the part that produces your Composite score - is now English, Math, and Reading only.
That does not mean Science disappeared. When you choose to take it:
- You receive a Science section score on the familiar 1 to 36 scale.
- That score is combined with your Math score to produce a STEM score, also on the 1 to 36 scale.
- The Science score is not averaged into your Composite.
This mirrors exactly how the Writing test has always worked: reported separately, useful for the programs that want it, but outside the Composite. The change matters most for STEM-bound students, because the STEM score is the place a strong Science result now shows up.
Enhanced versus legacy: a moving target
Because the change is recent, you may sit, or read about, two different versions of the test.
- The enhanced ACT form: Science is optional, 40 questions in 40 minutes, scored separately, feeding the STEM score but not the Composite. The enhanced paper test rolled out from September 2025.
- The legacy ("classic") ACT form: Science was part of the Composite, 40 questions in 35 minutes. The full-length legacy exam was offered through late 2025 (its final national school-day administration was around October 2025) before being retired.
When you study, work from the current official description on act.org and confirm which form your test date uses, because the time limit and whether Science counts toward the Composite are the two facts that differ.
What the format means for your plan
The format drives a small number of strategic decisions.
- Decide whether to take it. Because Science is optional, check whether your target colleges, scholarships, or programs want a Science or STEM score, and add the section if any do (see who should take ACT Science).
- Plan the clock. One minute per question is the budget. The reading-heavy passage will run slower, so you bank time on the figure-driven passages, as set out in pacing the 40-minute section.
- Study the right skill. Because the section tests reasoning, not recall, practise reading figures and experiments, not memorising biology and chemistry facts, as explained in what ACT Science actually tests.
Try this
Q1. State the two sections that became optional on the enhanced ACT, and name the three sections that now make up the Composite. [2 points]
- Cue. Optional: Science and Writing. Composite: English, Math, and Reading.
Q2. A student takes the enhanced ACT with Science and scores 30 on Science and 32 on Math. Which combined score does the Science result feed, and on what scale is it reported? [2 points]
- Cue. It feeds the STEM score (Science combined with Math), reported on the same 1 to 36 scale.
Exam-style practice questions
Practice questions written in the style of ACT exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
ACT Science (style)1 marksOn the enhanced ACT, a student answers all 40 Science questions in exactly 40 minutes. What is their average pace, in seconds per question? (A) 30 (B) 45 (C) 60 (D) 90Show worked answer →
A 1-point pacing calculation, the kind of arithmetic the section rewards.
The correct answer is (C), 60 seconds. The section is 40 minutes, which is seconds, and there are 40 questions. The average pace is seconds per question, or one minute each. (A) and (B) are too fast for the full section, and (D) would only let you reach about 27 questions. Knowing this one-minute pace is the foundation of every ACT Science timing plan.
ACT Science (style)1 marksA student takes the enhanced ACT with the optional Science section and earns 28 on Science. Where does this 28 appear in their score report? (A) It is averaged into the Composite. (B) It is reported as a Science section score and feeds the STEM score, but not the Composite. (C) It replaces the Reading score. (D) It is not reported at all.Show worked answer →
A 1-point item on how the enhanced ACT reports Science, a fact every test-taker should know before deciding to sit it.
The correct answer is (B). On the enhanced ACT, Science is optional, so it is reported as its own section score on the 1 to 36 scale and is combined with Math to form the STEM score, but it is not averaged into the Composite, which is now English, Math, and Reading only. (A) describes the legacy ACT, not the enhanced one. (C) and (D) are simply wrong, since Science is reported separately when taken.
Related dot points
- ACT Science measures science reasoning - interpreting data, understanding experimental design, and evaluating models and conclusions - rather than content recall, with almost every answer found on the page.
A focused answer on what the ACT Science section really measures: science reasoning rather than content recall. Covers the three core skills (reading data, understanding experiments, evaluating conclusions), why almost every answer is on the page, and the rare questions that need basic outside knowledge.
- The three ACT Science reporting categories - Interpretation of Data, Scientific Investigation, and Evaluation of Models, Inferences, and Experimental Results - and the skills and approximate proportions of each.
A focused answer on the three ACT Science reporting categories: Interpretation of Data (the largest), Scientific Investigation, and Evaluation of Models, Inferences, and Experimental Results. Covers the skills each one tests, their approximate proportions, and how recognising the category guides your answer.
- ACT Science scoring: a raw count of correct answers scaled to 1 to 36, no penalty for wrong answers, reported separately and combined with Math into the STEM score but excluded from the Composite on the enhanced ACT.
A focused answer on how the ACT Science section is scored: a raw count of correct answers converted to a 1 to 36 scale, no guessing penalty, reported as a section score, combined with Math into the STEM score, and excluded from the Composite on the enhanced ACT.
- Deciding whether to take the optional ACT Science section: weigh target-program requirements, STEM ambitions, your relative strength in Science, and the low downside, since a strong Science score lifts the STEM profile without affecting the Composite.
A focused answer on deciding whether to take the now-optional ACT Science section: checking the published requirements of target colleges and scholarships, considering STEM pathways, weighing your relative strength, and the low downside, since Science feeds the STEM score without touching the Composite.
- Pacing the ACT Science section: budgeting roughly one minute per question across the passages, spending less on figure-driven passages to bank time for the reading-heavy one, and never leaving a blank.
A focused answer on pacing the ACT Science section: about one minute per question (40 questions in 40 minutes on the enhanced ACT, 35 on the legacy form), banking time on figure-driven passages for the reading-heavy one, using a per-passage time check, and bubbling a guess on everything.
Sources & how we know this
- Description of the ACT Science Test — ACT, Inc. (2025)
- The ACT Test for Students: Enhancements — ACT, Inc. (2025)