ACT Science Section Guide

By Muntasir Jul 23, 2026 5 min read

TL;DR

ACT Science is now an optional section: it does not count toward your Composite score, which is averaged from English, Math, and Reading only. The section has 40 questions in 40 minutes, with 34 scored and 6 unscored field-test items. You will see three passage types: Data Representation (25-35% of questions), Research Summaries (45-60%), and Conflicting Viewpoints (15-20%). Questions test interpretation, analysis, evaluation, reasoning, and problem-solving in biology, chemistry, Earth and space science, and physics. Adding Science costs $5.00 on top of the $70.00 English/Math/Reading base fee for the 2026-27 cycle.

ACT Science tests how well you read data, not how well you memorized biology or chemistry facts. Deciding whether to add it means weighing 40 extra minutes on test day and a $5.00 add-on fee against what your target colleges and intended major require. This guide breaks down the section's format, timing, and three passage types, plus where to practice each skill.

Because the section no longer factors into your Composite score by default, some students skip it entirely. Others need it for scholarship requirements or program admission. Understanding the tradeoff starts with knowing what the section covers and which skills it rewards.

Is ACT Science Optional?

Under the Enhanced ACT, Science is an optional add-on section, the same way Writing is. Your Composite score is now averaged from English, Math, and Reading only, so skipping Science does not lower the Composite. If you take the Science section, ACT reports it as a separate score alongside your Composite, as confirmed in the Enhanced ACT FAQs.

ACT rolled out the optional format in stages. National online Saturday testing switched in April 2025, national paper Saturday testing followed in September 2025, and school-day testing through states and districts began moving to the new format in spring 2026, with exact timing set by each contract, per the Enhanced ACT FAQs.

For help deciding whether Science fits your testing plan, see our guide to choosing optional ACT Science and Writing.

Section Format and Timing

The Science section stays the same length whether or not you decide to add it. Here is the breakdown, per ACT's exam structure page:

Metric	Detail
Total questions	40
Scored questions	34
Unscored (field-test) questions	6
Time allowed	40 minutes

The 6 unscored questions sit mixed in with the 34 scored ones, and you won't know which is which, so treat every question the same way.

ACT does not publish a fixed passage count for Science under the Enhanced format, so expect a variable number of passages across the three passage types. Plan around the 40-question, 40-minute limit instead of a set passage count, and check ACT's exam structure page for the current official details.

Across all 40 questions, ACT measures interpretation, analysis, evaluation, reasoning, and problem-solving in biology, chemistry, Earth and space science, and physics, according to ACT's overview for students. Reading skill matters more than subject recall. Most passages give you the science content you need, then ask you to work with it.

The Three Passage Types

Every Science section draws from three passage formats, each testing a different skill and appearing in a different share of questions, per ACT's Description of Science Test.

Passage Type	Share of Questions	What It Tests
Data Representation	25-35%	Reading tables, graphs, and diagrams, plus interpolating and extrapolating trends
Research Summaries	45-60%	Experimental design and interpreting results across related experiments
Conflicting Viewpoints	15-20%	Comparing explanations for the same phenomenon disagreeing over premises or data

Data Representation

Data Representation passages present graphic and tabular material: charts, graphs, tables, and diagrams. Questions ask you to read values directly off a chart, spot a trend, and extend the trend beyond the plotted data through interpolation or extrapolation. These passages make up 25-35% of the section's questions.

Research Summaries

Research Summaries passages describe one or more related experiments and their results. Questions focus on experimental design: what variable changed, what stayed constant, and what the results show. This is the largest share of the section at 45-60% of questions.

Conflicting Viewpoints

Conflicting Viewpoints passages present two or more explanations for the same phenomenon. The explanations disagree because they start from different premises or incomplete data, not because one side made an error. Questions ask you to identify where the viewpoints agree, where they diverge, and why. This passage type covers 15-20% of the section's questions.

Reading Graphs and Tables Is the Core Skill

Data-reading drives your score more than science background. Every passage type asks you to work directly with a figure, table, or dataset in some way. Build these habits before test day:

Read axis labels and units before looking at the data points.
Trace one variable at a time across a table or graph.
Check whether a trend is linear before you extrapolate beyond the plotted range.
Compare experimental setups side by side rather than reading each one in isolation.
Note where two viewpoints start from different assumptions, not only different conclusions.

ACT Science Fees and Registration

Adding Science to your test date costs extra. Here are the 2026-27 registration fees, per ACT's registration fees page:

Registration Option	Fee
English/Math/Reading (EMR) base	$70.00
Science add-on	$5.00
Full test (EMR + Science + Writing)	$100.00

You are allowed to add or drop the Science section through the late registration deadline, according to ACT's fee schedule. Decide early where possible, since late changes come with the standard late-registration fee.