Commonly Confused Words

Intermediate · Writing Mechanics

Some word pairs sound the same or look similar, and even native speakers mix them up. Learning the difference once will make your writing noticeably more accurate.

The trick for most of them is to expand the contraction or ask what job the word is doing (possession? being? comparison?).

Rules & examples

1. your (possession) vs. you're (you are).

   If you can say "you are", use "you're".

   • Your book is here.
   • You're late.
2. there (place) vs. their (possession) vs. they're (they are).

   there has "here" inside it (place); their = belonging; they're = they are.

   • Sit there.
   • Their house.
   • They're happy.
3. then (time) vs. than (comparison).

   then = next/at that time; than = used to compare.

   • We ate, then left.
   • Taller than me.
4. affect (verb) vs. effect (noun).

   affect = to influence (action); effect = the result (thing).

   • Rain affects traffic.
   • The effect was huge.
5. fewer (countable) vs. less (uncountable).

   fewer for things you count; less for masses.

   • fewer people
   • less water
6. lose vs. loose; to / too / two.

   lose = not win/misplace; loose = not tight. too = also/excessively; two = 2.

   • Don't lose the key.
   • a loose shirt
   • me too, two cats, go to work

Tips to remember

• Expand the apostrophe to test: if "you're" = "you are" fits, it's correct; if not, use "your".
• affect vs effect: A = Action (affect, verb), E = End result (effect, noun).

Common mistakes

• ✗ Your welcome. → ✓ You're welcome. — The phrase means "you are welcome".
• ✗ I have less friends now. → ✓ I have fewer friends now. — "Friends" is countable, so use "fewer".