The ACT STEM score is a 1–36 blend of Math and Science. You only get one if you sit optional Science. It is not the Composite, and it does not replace a low Math score.
How it is built
ACT combines Math and Science into one STEM number. A 34 Math and a 28 Science will not look like a 34 STEM. If you skip Science, you have no STEM score to send.
Who should care
Engineering, CS, and some nursing programs still glance at Science or STEM. Do engineering colleges care about Science. What a good Science number is: a good Science score.
Who can ignore it
If no college on the list asks for Science or STEM, skip the extra 40 questions and protect English, Math, and Reading. Is Science optional.
The bottom line
STEM is Math plus Science, optional to produce, never a substitute for the Composite. Sit Science only if someone will read the pair.
Start practicing
Start with a free diagnostic, then drill your weak spots with 15-question quizzes and track how you're doing across Reading, English, and Math. Compare plans whenever you're ready to go further.
This article offers general ACT prep guidance. The ACT can change from year to year, including its format, scoring, policies, test dates, and fees, so always confirm the latest details on the official ACT website at act.org before you make decisions. ACT® is a registered trademark of ACT, Inc. thirty-six is not affiliated with, endorsed by, or sponsored by ACT.