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10 Common Grammar Mistakes (and How to Fix Them)

Most grammar mistakes fall into a short list of repeat offenders. Here are ten of the most common, with quick fixes.

1. Its vs. it's — "it's" is always short for "it is" or "it has"; everything else is "its."
2. Their / there / they're — possession, place, and a contraction of "they are," respectively.
3. Comma splices — joining two full sentences with just a comma. Use a period, semicolon, or a conjunction instead.
4. Dangling modifiers — a descriptive phrase that doesn't logically attach to the subject that follows it.
5. Subject-verb agreement — especially with compound or collective subjects.
6. Misused apostrophes in plurals — "1990s," not "1990's."
7. Who vs. whom — "who" is a subject, "whom" is an object.
8. Run-on sentences — several ideas strung together without a clear break.
9. Double negatives — "I don't know nothing" should be "I don't know anything."
10. Misplaced only — "only" should sit right next to the word it modifies to avoid changing the meaning.

Most of these are easy to miss in your own writing because you already know what you meant. Reading a draft out loud, or running it through a grammar checker, catches far more of these than a silent read-through.

Key takeaways

• Its/it's and their/there/they're are the most frequent mix-ups by far.
• Comma splices and run-ons usually need a period, semicolon, or conjunction to fix.
• A grammar checker catches far more of these than a silent read-through.

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