SAT Writing · 7 min read · Published January 8, 2026
SAT Punctuation Rules: A Complete Summary
Every punctuation rule tested on the Digital SAT, compressed into a single cheat sheet you can memorize in an afternoon.
The Essential Marks
The SAT tests a small, repeatable set of punctuation patterns.
- Period: ends an independent clause.
- Comma: separates elements, sets off non-essential information.
- Semicolon: joins two independent clauses, or separates list items with internal commas.
- Colon: introduces a list or elaboration after a complete sentence.
- Em dash: inserts extra information; always in pairs mid-sentence.
- Apostrophe: shows possession or contraction.
The Single Biggest Trap
Comma splices — two independent clauses joined by just a comma — are the most frequent wrong-answer pattern. When two complete sentences meet, you almost always need a semicolon, period, or comma + FANBOYS.
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