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An apostrophe on the SAT answers one question: does this noun own something, or is it just plural? The test buries the decision inside long sentences, but the rule underneath is short. Decide whether the word shows possession, then decide whether the owner is singular or plural, and the placement follows.
Use an apostrophe to show possession or to mark a contraction, never to make a noun plural. For a singular owner, add apostrophe plus s. For a plural owner already ending in s, add only an apostrophe after the s. Possessive pronouns such as its and whose take no apostrophe at all.
Key takeaways
- An apostrophe shows ownership or marks a contraction. A plain plural takes no apostrophe.
- Singular owner: add 's (the student's essay). Plural owner ending in s: add just ' (the students' essays).
- Possessive pronouns (its, whose, their, your) never take an apostrophe. It's, who's, they're, and you're are contractions.
- The signal on the SAT is whether the next word is a noun being owned. No owned noun means no apostrophe.
- The SAT grammar rules guide maps every convention family. This page is the apostrophe rules only.
What are the SAT apostrophe rules?
| Form | Pattern | Example |
|---|---|---|
| Singular possessive | noun + 's | the scientist's notebook |
| Plural possessive (ends in s) | noun + s + ' | the scientists' notebooks |
| Plural possessive (irregular) | plural + 's | the children's section |
| Contraction | two words + ' | it's for it is |
| Plain plural | noun + s, no apostrophe | three scientists |
The most common miss is adding an apostrophe to a simple plural: the printer's are broken for more than one printer. If the noun owns nothing and no letters are missing, drop the apostrophe. Plurals go unmarked.
How do you tell a possessive from a plural?
Ask what comes right after the noun. A possessive is almost always followed by another noun, the thing being owned: the teacher's plan, the teachers' lounge. A plain plural stands alone or is followed by a verb: the teachers agreed. If nothing is being owned, the apostrophe has no job.
Plural (no apostrophe)
The engineers reviewed the bridge. The engineers are doing the reviewing, not owning a noun, so the word stays a plain plural.
Possessive (apostrophe)
The engineers' report was late. The report belongs to the engineers, so the plural owner takes an apostrophe after the s.
When is it its and when is it it's?
This is the pair the SAT tests most, because the possessive form breaks the usual habit. Its is possessive and takes no apostrophe, the same as his or hers. It's always expands to it is or it has. The reliable check is to read the sentence with it is: if it survives, write it's; if it collapses, write its.
- Possessive: The theory lost its appeal. Ownership, no apostrophe.
- Contraction: It's a fragile theory. Expands to it is, so it takes an apostrophe.
- Same test for who's and whose: whose shows ownership; who's means who is or who has.
- For the pronoun side of this in full, the SAT pronoun rules guide handles case and agreement.
Can you try one SAT apostrophe question?
By the end of the migration season, the nests along the cliff were empty, the young having already flown south.
Which choice completes the text so that it conforms to the conventions of Standard English?
Decide owner or plural, then singular or plural owner, and place the apostrophe on fresh conventions questions.
Practice SAT apostrophes →Frequently asked questions
- What are the apostrophe rules on the SAT?
- Use an apostrophe to show possession or to mark a contraction. A singular owner takes apostrophe plus s, a plural owner ending in s takes just an apostrophe, and a plain plural takes no apostrophe at all.
- How do you make a plural noun possessive?
- If the plural already ends in s, add only an apostrophe after it, as in the students' desks. If the plural is irregular and does not end in s, add apostrophe plus s, as in the children's books.
- Is it its or it's?
- Its is possessive and takes no apostrophe. It's is a contraction meaning it is or it has. Read the sentence with it is: if that works, use it's, and if it does not, use its.
- Does the SAT test apostrophes?
- Yes. Apostrophe questions appear in the Standard English Conventions part of the Reading and Writing section, usually asking you to choose between a possessive, a plural, and a contraction.
- Why is an apostrophe wrong on a plain plural?
- A plain plural shows there is more than one of something, which needs no apostrophe. Adding one signals ownership or a contraction, so it misreads the sentence when the noun owns nothing.