who than (then)

Mixing who and than breaks sentences because they serve different jobs: who (or whom) introduces a person in a relative clause; than marks a comparison. Below are quick tests, clear rules, many copy-ready wrong/right pairs for work, school, and casual contexts, step-by-step rewrites, a memory trick, and a short tool suggestion.

Quick answer

Use who (or whom) to name or describe a person; use than to compare. If the phrase answers "Who?" use who. If it answers "How much more?" or shows a preference, use than.

Who = relative pronoun for people (the person who called).
Than = comparative connector (better than, taller than).
Fast test: are you comparing? → than. Are you identifying a person? → who.

Core explanation: roles of who vs. than

Who (subject) or whom (object) introduces a clause that adds information about a person: "the student who won." Than introduces a comparative clause: "taller than I expected."

Relative clause: noun + who/whom + verb - identifies a person.
Comparative clause: comparative adjective/adverb + than + noun/pronoun/clause - shows difference or preference.
If the clause answers Who? or Which person? use who; if it answers Which is greater or preferred? use than.

Grammar specifics: clause shapes and pronoun cases

Who is the subject inside a relative clause; whom is the object. After than, pronoun case depends on formality: "than I (am)" is formal, "than me" is common in speech. None of that makes who acceptable where a comparison is intended.

Use whom when it's the object in formal writing: "the person whom we hired."
After than, use the full clause if you want formal clarity: "She is taller than I (am)." Informal: "She is taller than me."

Wrong: He is taller who his cousin.
Right: He is taller than his cousin.

Real usage and tone: formal vs. casual

In professional or academic writing, keep comparisons clear with than and choose pronoun case intentionally. In casual writing, "than me" is fine; but never replace than with who.

Formal: "than I (am)" or repeat the verb: "than he is."
Casual: "than me" is acceptable-prioritize clarity over strict case.

Wrong: Our report is more thorough who last year.
Right: Our report is more thorough than last year's.

Use tools that teach, not just fix

Choose a checker that explains why it suggests than so you learn the rule instead of copying blindly. Review flagged who/than cases to build intuition.

Examples you can copy: work, school, and casual pairs

Copy the right-hand sentences when your draft shows the wrong pattern. These are short, clear swaps you can paste and adapt.

Work examples

Wrong: The manager who the team prefers will lead the project.
Right: The manager than the team prefers will lead the project. (Better: The manager the team prefers will lead the project.)
Wrong: Our new system is more efficient who the old one.
Right: Our new system is more efficient than the old one.
Wrong: She handles client calls who anyone else in the office.
Right: She handles client calls better than anyone else in the office.

School examples

Wrong: The student who the class admired got the award.
Right: The student whom the class admired got the award.
Wrong: This assignment is harder who the last one.
Right: This assignment is harder than the last one.
Wrong: He studies more who his peers.
Right: He studies more than his peers.

Casual examples

Wrong: She's funnier who her sister.
Right: She's funnier than her sister.
Wrong: The coffee here tastes better who the one downtown.
Right: The coffee here tastes better than the one downtown.
Wrong: He arrived earlier who I thought.
Right: He arrived earlier than I thought.

How to fix your sentence: step-by-step rewrites

Identify intent: is the clause comparing? Look for more, less, better, worse, rather, prefer, taller, earlier.
If it's a comparison, replace who with than. If that sounds awkward, repeat the noun or add the verb after than.
Read aloud. If meaning is unclear, rewrite the clause so the comparison stands on its own.

Rewrite:
Wrong: The book was more engaging who the movie. →
Right: The book was more engaging than the movie.
Rewrite:
Wrong: He seemed happier who I saw him last year. →
Right: He seemed happier than when I saw him last year.
Rewrite:
Wrong: She's better who handling client issues. →
Right: She's better at handling client issues than her predecessor.

Memory trick: quick tests to use while writing

Ask: Am I naming someone or comparing two things/people/ideas? If naming, use who. If comparing, use than.

Swap test: replace the clause with a noun or "that." If the sentence still reads as a comparison, keep than.
Sound test: say it aloud-"better than" sounds natural; "better who" should sound wrong.

Similar mistakes to watch for

Be careful with then vs. than, and who vs. whom. That/which apply to things; who applies to people. A comparison always needs than, regardless of which pronoun you might otherwise use.

Wrong: She arrived earlier then I did.
Right: She arrived earlier than I did.
Who vs. whom: "the author who writes" (subject) vs "the author whom we invited" (object).

Hyphenation: when "more-than" can be hyphenated

"More than" is usually two words. Hyphenate when the entire comparative phrase is a compound modifier before a noun: "a more-than-adequate response."

Use hyphens for pre-noun compound modifiers: "a more-than-satisfactory result."
Hyphens don't fix a wrong who/than choice-fix the grammatical role first, then apply hyphenation rules.

Spacing and punctuation: small editing traps

Normal spacing applies. Watch comma changes: nonessential relative clauses take commas; comparative clauses do not. Deleting words during edits can accidentally convert a comparative into a descriptive clause.

Relative with commas: "My sister, who lives in Boston, is visiting."
Comparison without commas: "My sister is older than I am."

FAQ

Can I ever substitute who for than?

No. Who introduces a person; than marks a comparison. Replacing than with who in a comparative sentence is incorrect.

Is "than me" wrong?

"Than me" is common and fine in informal speech. For formal writing, prefer "than I" (short for "than I am").

My sentence has both a person and a comparison-how do I fix it?

Separate roles. Wrong: "She is smarter who her colleague." Right: "She is smarter than her colleague." If you must identify someone, add a relative clause: "She, who mentors new hires, is smarter than her colleague."

Why do grammar checkers change who to than?

Checkers detect comparative words and suggest than when the clause functions as a comparison. Review each suggestion to ensure it matches your intended meaning.

What quick edit helps when the swap sounds awkward?

Repeat the noun or add the verb after than: awkward "than her" → clearer "than her predecessor" or "than she is."

Want a quick check?

Paste a sentence into a grammar tool that explains edits (not just corrects) to see why a change is suggested, then copy a tested rewrite from above. Practice the memory tricks until choosing who vs. than becomes automatic.