10 Common Grammar Mistakes and How to Avoid Them
These quick explanations show how to spot frequent grammar mix-ups and make your writing clearer with simple edits.
1. Your and you’re
Your shows that something belongs to you; you’re is the contraction of you are. The two can sound identical, so check what the sentence means. Incorrect: “Your going to like this book.” Correct: “You’re going to like this book.” A useful test is to replace the word with you are. If the sentence still works, use you’re.
2. There, their, and they’re
There points to a place or introduces a statement, their means something belongs to them, and they’re means they are. Incorrect: “Their leaving there coats over their.” Correct: “They’re leaving their coats over there.” Pause at each word and identify its job: location, ownership, or a shortened phrase. That small check catches most mix-ups.
3. Its and it’s
It’s means it is or it has. Its is the possessive form, like her or his, and does not use an apostrophe. Incorrect: “The printer lost it’s connection.” Correct: “The printer lost its connection.” Try expanding it’s into it is. If that replacement does not make sense, use its.
4. Affect and effect
Affect is usually a verb meaning to influence; effect is usually a noun meaning a result. Incorrect: “The new schedule had a positive affect.” Correct: “The new schedule had a positive effect.” In another sentence, “The schedule affected attendance” uses affect as the action. Remember the usual pattern, then check for exceptions only when the sentence is unusually formal or technical.
5. Subject-verb agreement
A singular subject takes a singular verb, and a plural subject takes a plural verb. Extra words between them can hide the subject. Incorrect: “The list of supplies are on the desk.” Correct: “The list of supplies is on the desk.” The subject is list, not supplies. Find the main subject first, then match the verb to it.
6. Pronoun agreement
A pronoun should clearly match the noun it refers to in number and person. If the noun is plural, use a plural pronoun. Incorrect: “The employees left her badges at reception.” Correct: “The employees left their badges at reception.” Also check that a pronoun has one clear reference. When a sentence could point to two people or things, repeat the noun instead of making readers guess.
7. Comma splices
A comma splice joins two complete sentences with only a comma. Give each sentence a proper connection. Incorrect: “The train was delayed, we took a taxi.” Correct: “The train was delayed, so we took a taxi.” You could also use a period or a semicolon. A comma alone is not strong enough to join two independent clauses.
8. Apostrophes in plurals
Apostrophes usually show possession or a contraction, not a regular plural. Incorrect: “We ordered three sandwich’s.” Correct: “We ordered three sandwiches.” To show ownership, add an apostrophe in the right place: “the sandwich’s filling” belongs to one sandwich, while “the sandwiches’ fillings” belong to several. First decide whether the word is plural or possessive.
9. Fewer and less
Use fewer with items you can count separately, and less with an amount or quantity treated as a whole. Incorrect: “There were less chairs in the room.” Correct: “There were fewer chairs in the room.” By contrast, less noise and less time are standard because noise and time are amounts in these examples. Ask whether you can count the items one by one.
10. Then and than
Then refers to time or what happens next. Than compares things. Incorrect: “This route is shorter then the old one.” Correct: “This route is shorter than the old one.” In a sequence, use then: “Check the address, then send the letter.” The letters differ by one, so proofread comparison sentences carefully.
Give your writing one final check
Many grammar errors disappear when you read a sentence slowly and check what each word is doing. Look for the subject and verb, confirm that pronouns have clear references, and read punctuation aloud to hear where ideas should pause. For a quick second pass, paste your draft into the Grammar Checker to catch common mistakes automatically. Review its suggestions before accepting them; context matters, and your judgment helps preserve the meaning and voice you intend.