What is (the) reason?

The words their, there, and they're sound the same but play three different roles. Use the quick tests below, copy-ready rewrites, and the example sets for work, school, and casual writing to fix mistakes fast.

If you need to check a sentence, expand contractions, ask "whose?", and test for place/existence. If that still feels uncertain, use one of the rewrites provided.

Quick check: which one to use

'Their' = possession. 'There' = place or 'there is/are.' 'They're' = contraction of 'they are.'

'Their' answers the question: whose? → their jacket.
'There' points to location or introduces existence: over there; there are two.
'They're' = they + are. Expand it to check if it fits.

How each form works (core explanation)

'Their' is a possessive adjective or a possessive pronoun in constructions (their idea; the idea is theirs). It never takes an apostrophe.

'There' is an adverb of place or an existential marker. Use it for locations (Put it there) or sentences like there is/are.

'They're' contracts they + are. If expanding to "they are" reads properly, they're is correct.

Test 1 (contraction): Can you replace it with "they are"? If yes → they're.
Test 2 (possession): Ask "whose?" If the answer is "them," use their/theirs.
Test 3 (place/existence): Is it location or "there is/are"? Then use there.

Memory tricks that stick

Simple cues help: they're has an apostrophe because it's two words. There contains "here" - think place. Their ends with "r", like owneR ends with "r" - think possession.

'They're' = they + are (apostrophe = missing letters).
'There' = here (place).
'Their' = whose? → their.

Real usage and tone: why it matters

In formal writing, prefer "they are" over they're unless the tone allows contractions. A single misplaced their/there/they're can read careless in reports or public copy.

Formal: spell out ("they are") or double-check ownership.
Emails/IMs: contractions are fine, but verify 'their' for possession.
Public copy: consistency matters; readers notice small errors.

Common examples (wrong → right) - read, compare, copy

Six immediate wrong/right pairs followed by grouped examples for work, school, and casual contexts.

Wrong: Their going to the interview at 2 pm.
Right: They're going to the interview at 2 pm.
Wrong: I left my notes over they're.
Right: I left my notes over there.
Wrong: There project won the award.
Right: Their project won the award.
Wrong: Is this their's or yours?
Right: Is this theirs or yours?
Wrong: Theyre checking the server now.
Right: They're checking the server now.
Wrong: Their is an update on the dashboard.
Right: There is an update on the dashboard.

Work: Please move the files to their folder on the server.
Work: There are three action items for the team today.
Work: They're presenting the findings in the 10 am meeting.
School: Their hypothesis predicted a stronger effect.
School: There are two key sources you should cite.
School: They're required to submit the survey by Friday.
Casual: Put the jacket over there on the chair.
Casual: That's their playlist - it's great.
Casual: They're gonna be late, start without them.

Try your own sentence

Test the whole sentence. Context usually makes the correct choice obvious: expand contractions, ask "whose?", or try "over there" to see if location fits.

Fix your sentence: step-by-step rewrites you can copy

Three quick steps: 1) Expand contractions. 2) Ask "whose?" 3) Replace with "over there" or test "there is/are." If unsure, paste one of these rewrites.

Step 1: If "they are" reads right, use they're.
Step 2: If "whose?" yields ownership, use their/theirs.
Step 3: If it indicates place or existence, use there.

Wrong: There house finally got their keys back.
Rewrite: Their house finally got its keys back; they're relieved.
Wrong: Is this there notebook?
Rewrite: Is this their notebook?
Wrong: I put it over their, not they're.
Rewrite: I put it over there, not in their bag.
Wrong: Their going to submit there work but theyre unsure.
Rewrite: They're going to submit their work, but they're unsure about the formatting.

Spacing, apostrophes, and hyphenation - tiny errors that stand out

Never add an apostrophe to possessive pronouns: not 'their's' or 'its' with an apostrophe. Use theirs and its.

No hyphens are needed in these words. Watch for autocorrect joining words (e.g., Theyre or theirhouse). Keep one space between words.

'Their' = possessive adjective; 'theirs' = independent possessive pronoun.
'It's' = it is / it has. 'Its' = possession.
Autocorrect can join or swap words - scan short messages before sending.

Short grammar reference

'Their' - possessive adjective or part of a possessive construction; never takes an apostrophe.

'There' - adverb of place or existential placeholder; ensure verb agreement in "there is/are" sentences.

'They're' - contraction of they + are; expand it to confirm fit.

Examples: their idea / the idea is theirs.
There is a problem vs There are two problems - verb must agree with the real subject.
They're always expands to they are and must make grammatical sense when expanded.

Similar mistakes to watch for

Use the same substitution tests for your/you're and its/it's. Errors often cluster; if you spot one, check the others.

Also watch affect/effect and fewer/less in more complex edits.

your / you're - expand "you're" to "you are".
its / it's - "it's" = it is/has; "its" = possession.
affect (verb) vs effect (noun) - test with "influence" or "result."

Usage: Wrong: Your the best person for this. →
Right: You're the best person for this.
Usage: Wrong: Its scope is limited. →
Right: Its scope is limited. (
Correct: no apostrophe.)

FAQ

Is 'there' ever possessive?

No. There marks place or existence. Use their or theirs for possession.

How can I test if 'they're' is correct?

Expand it to "they are." If the sentence still makes sense, they're is right.

Which is correct: 'their's' or 'theirs'?

'Their's' is incorrect. Use theirs for the standalone possessive pronoun.

Should I avoid 'they're' in formal writing?

Many formal contexts avoid contractions. Prefer "they are" in reports and academic writing unless a style guide allows contractions.

Can spellcheck/autocorrect be trusted for these errors?

Not always. Spellcheck may accept all three words as valid. Use the substitution tests to be certain.

Quick last check before you send

Run the three tests: expand contractions, ask "whose?", and check for place/existence. If a rewrite below fits, copy it into your message.

For extra assurance, paste the sentence into a grammar tool that explains the correction so you learn the rule, not just the fix.