The main idea is what the passage is mainly trying to say or support; it is the most important point, claim, or argument.

Think of the main idea like Main St. in a small town—all of the other streets connect to it. In the same way, all the details in a paragraph should connect to the main idea.

While the subject/topic of a passage is usually just a phrase, the main idea is a broad statement in the form of a complete sentence.

Ex. Subject/Topic (very broad): high blood pressure
Ex. Main Idea (broad): Sodium can cause high blood pressure.
Ex. Detail (more specific): Excess sodium results in water retention that can increase pressure in blood vessels.

Common ways to ask for the main idea:

The central idea of this passage is…
The author’s main point is…
The main idea of the passage...

Summary

When looking for the main idea, start by asking, “What is the most important point, claim or argument that the author wants me to understand?”
Look for a broad statement that covers all the details in the paragraph or passage.
When selecting your answer, ask, “Do all the other sentences tell more about this idea?”

Ready to check your knowledge? Take the Main Idea and Central Point Practice Quiz