The ACT STEM score is the rounded average of Math and Science section scale scores from the same administration. It is separate from the enhanced Composite, which uses English, Math, and Reading.
If you do not have both Math and Science results for the relevant administration, do not invent a STEM score by filling in a blank or borrowing an unrelated practice result. ACT’s definition specifically ties the two sections to the same administration. ACT STEM definition
Calculate STEM with scale scores
Suppose a student earns Math 27 and Science 30.
The average is (27 + 30) ÷ 2 = 28.5. Rounded to the nearest whole number with a half upward, the STEM score is 29. The official practice scoring instructions provide the rounding rule. ACT Practice Test 1 scoring instructions
Here are additional original examples:
| Math | Science | Average | Rounded STEM |
|---|---|---|---|
| 24 | 24 | 24 | 24 |
| 25 | 26 | 25.5 | 26 |
| 31 | 28 | 29.5 | 30 |
| 34 | 30 | 32 | 32 |
These calculations use section scale scores. They do not use the number of questions correct or the percentage of a worksheet completed.
Convert raw counts before averaging
A raw Math count and a raw Science count are not directly comparable score ingredients. Their sections have different question structures and form-specific conversion tables.
If you completed a supported official practice form, use its scoring guide to obtain Math and Science scale scores first. Then calculate the rounded average.
The ACT score calculator can perform those steps for its named forms. If you know only all-question correct totals, the section results may be ranges because the totals do not identify correct unscored questions. The STEM output should preserve that uncertainty rather than display an unjustified single number.
Do not take a raw count from an original exercise set and place it into a convenient official chart. The resulting number would not be a valid conversion for that set.
STEM and Composite can tell different stories
Consider this hypothetical profile:
| Section | Scale score |
|---|---|
| English | 23 |
| Math | 30 |
| Reading | 25 |
| Science | 32 |
The enhanced Composite is (23 + 30 + 25) ÷ 3 = 26. The STEM average is (30 + 32) ÷ 2 = 31.
There is no contradiction. The student’s Math and Science results are stronger than the three-section average that includes English and Reading.
Another student could have English 31, Math 23, Reading 30, and Science 25. Their Composite would be 28, while STEM would be 24. The profile suggests different preparation questions.
Neither number should replace the individual section scores when you plan study work.
The same STEM score can hide different needs
A student with Math 28 and Science 28 has STEM 28. A student with Math 34 and Science 22 also has STEM 28.
The first student has a balanced pair. The second has a large difference between the sections. If both follow an identical “STEM 28 improvement plan,” one or both may waste time.
Ask what happens inside each section:
- Is Math limited by concept knowledge, modeling, arithmetic, or pacing?
- Is Science limited by reading displays, comparing studies, background knowledge, or time?
- Are errors repeated across fresh material?
- Do corrections hold up when the answer key is no longer visible?
The combined score identifies a broad area. The error record identifies the next task.
Science is not only memorized content
A student who enjoys laboratory science may still need practice extracting information from unfamiliar graphs and study descriptions. A student who is strong at reading graphs may still encounter questions requiring relevant background knowledge.
For an original example, imagine a graph showing plant growth under different light durations. Before interpreting a trend, identify the units, the group represented by each line, and whether the graph displays height or change in height. A correct general belief about plants cannot rescue a misread axis.
This is why a useful Science review records the exact source of an error. “I am bad at science” is too broad to lead to a productive lesson.
A Math–Science review exercise
After a supported practice attempt, select one missed Math question and one missed Science question. Explain each without looking at the solution.
For Math, write the requested quantity, the model, the calculation, and a check. For Science, write the question’s task, the relevant evidence, and why an alternative answer goes beyond or contradicts that evidence.
Then solve a fresh problem that uses the same reasoning. The second attempt tests whether you learned a transferable method rather than recognized the original answer.
Schedule this review before taking another full test. A new score without changed preparation often tells you less than a careful review of the existing one.
What if Science is not part of your test?
A missing Science result does not become zero, and it does not reduce the enhanced Composite. It means you do not have the Science input needed for that administration’s STEM calculation.
Whether Science is required or useful for your goals depends on the testing program and the relevant institutions. State and District administrations may include it under their contract, while students in other programs may have a registration choice. ACT Science-choice policy
Check the specific policy before assuming that every future engineering applicant must take it, or that no applicant needs it.
Do not turn STEM into an admission cutoff
A STEM score is a reported measure, not a universal admissions threshold. A college or program decides how to use it, if at all.
Before making a registration or reporting decision, check the official policy for your application year and program. Separate a published requirement from a recommendation and from your own preference to provide additional evidence.
Avoid translating a STEM score into a promise about a major. Performance on two test sections does not decide whether you can study a field or succeed in it.
Keep the record clear
For each attempt, save the form or administration date, Math score, Science score, STEM result, timing conditions for practice, and one priority for review. Keep official reports separate from your own practice calculations.
SHSPrep’s ACT program includes lessons, targeted practice, and two original full-length mock tests with raw performance results. Use the STEM score as a starting point for understanding your Math–Science profile, then work on the specific reasoning that the combined number cannot show.