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Commonly confused words: affect vs effect and more

PT Phrasera Team · 6 min read · June 2026

Most word mix-ups come from a small set of look-alike, sound-alike pairs — and each has a simple trick to keep them straight. These slip past spellcheck because the wrong word is still spelled correctly, so they’re worth memorizing once.

Affect vs effect

Affect is usually a verb (to influence); effect is usually a noun (the result). Trick: Affect = Action (verb); Effect = End result (noun). “The weather affects my mood” → “the effect was obvious.”

Their / there / they’re

  • Their = possession (“their car”).
  • There = place (“over there”).
  • They’re = they are (“they’re late”).

Trick: “they’re” only works if you can expand it to “they are.”

Your vs you’re

Your = possession (“your idea”); you’re = you are (“you’re right”). Same expand-it test.

Its vs it’s

Its = possession (“the dog wagged its tail”); it’s = it is / it has (“it’s raining”). The apostrophe means a missing word, not possession — this trips up almost everyone.

Then vs than

Then = time or sequence (“we ate, then left”); than = comparison (“bigger than before”).

Fewer vs less

Fewer for things you can count (“fewer emails”); less for things you can’t (“less time”).

Lose vs loose

Lose = to misplace or not win (“don’t lose it”); loose = not tight (“a loose screw”).

Complement vs compliment

Complement = completes something (“wine complements the meal”); compliment = praise (“a kind compliment”).

How to catch these every time

These errors hide from spellcheck but not from a grammar tool that reads context. After drafting, run your text through the grammar checker — it flags the wrong-word slips a spell checker misses. And when you read your work aloud, your ear often catches what your eye accepted — pair it with a proofreading checklist.

Learn the tricks once, and these stop being mistakes you make and become mistakes you spot.

AI-powered — please review results before use.

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