Who + verb (who know's/knows)

When who is the subject of a question, use normal subject-verb agreement. The frequent errors are using the wrong verb form (Who know? Who know's?) or leaving out the auxiliary when who is the object.

Quick answer: Which verb goes after who?

Treat who like the subject it represents. Use the verb form that matches number and tense: third-person singular present (Who knows?), plural when who refers to multiple people (Which team members are coming?), past tense for past events (Who came?), and auxiliary + base verb when who is the object (Who did you call?).

If who = one person (he/she): use third-person singular present (Who knows?).
If who = multiple people: use plural verb or rephrase for clarity (Which people know?).
If who is the object: use an auxiliary + base verb (Who did you see?).

Core explanation: how to pick the verb after who

In a question where who performs the action, treat who as the subject and choose the verb to match tense and number: add -s in the present for singular, use past forms for past tense, and will/shall for future.

When who is the object, include an auxiliary (do/does/did/will) and keep the main verb in the base form.

Subject + present (singular): Who + verb+s → Who knows?
Subject + past: Who + past verb → Who wrote the report?
Object: Who + auxiliary + base verb → Who did you invite?
Future: Who + will + base verb → Who will attend?

Wrong: Who know the answer?
Right: Who knows the answer?
Wrong: Who write the report?
Right: Who wrote the report?

Grammar notes: auxiliaries, contractions and number tests

Use auxiliaries (do/does/did/will/have) when who is not the subject. Contractions like who's = who is / who has are standard. Never use an apostrophe to form a regular verb ending (know's is incorrect).

Quick number test: substitute he/she/they. The verb that fits the substitute is the correct choice for who.

If substitution needs does/did, use an auxiliary: He did this → Who did this?
Who's = who is / who has (Who's coming? / Who's finished?).
No apostrophes on verb endings: knows (correct), know's (wrong).

Examples: wrong → right (work, school, casual)

Below are three workplace, three school, and three casual wrong/right pairs. Each correct version reads naturally in context.

Work - Wrong: Who manage the account now?
Right: Who manages the account now?
Work - Wrong: Who lead the meeting yesterday?
Right: Who led the meeting yesterday?
Work - Wrong: Who have the latest version of the deck?
Right: Who has the latest version of the deck?
School - Wrong: Who write the bibliography?
Right: Who wrote the bibliography?
School - Wrong: Who volunteer for the presentation?
Right: Who volunteers for the presentation?
School - Wrong: Who know the answer to question three?
Right: Who knows the answer to question three?
Casual - Wrong: Who want to grab lunch?
Right: Who wants to grab lunch?
Casual - Wrong: Who coming tonight?
Right: Who's coming tonight?
Casual - Wrong: Who have the keys?
Right: Who has the keys?

Real usage and tone: when shortcuts are fine and when to be precise

Clipped forms like "Who coming?" are common in speech and quick chat. For emails, reports, essays and formal messages, use full subject-verb agreement.

If the number is unclear, rephrase. Make plurals explicit when needed: "Which team members are coming?" is clearer than "Who are coming?"

Casual: "Who coming?" in group chat is fine.
Formal: "Who is coming to the meeting?"
Speech: "Who's got time?" Email: "Who has time to review this by Friday?"
Avoid apostrophes on verbs - they mark possession or contraction, not regular endings.

Try your own sentence

Test the whole sentence in context rather than the phrase alone. Substitute he/she/they or turn the question into a statement to see which verb form fits.

How to fix your sentence: rewrite help and templates

Apply the swap test (he/she/they), then pick a template below. These templates cover present, past, future and object questions.

Subject, present, singular: Who + verb + s → Who knows? Who wants? Who understands?
Subject, past: Who + past verb → Who called? Who wrote? Who left?
Object: Who + did/didn't + base verb → Who did you call? Who didn't you invite?
Future: Who + will + base verb → Who will attend? Who will lead?

Rewrite:
Wrong: Who do this? →
Right: Who did this?
Rewrite:
Wrong: Who want the job? →
Right: Who wants the job? (or: Who would like the job?)
Rewrite:
Wrong: Who know the editor? →
Right: Who knows the editor? (If you mean "who was asked," write: Who did you ask about the editor?)
Rewrite:
Wrong: Who are in charge? →
Right: Who is in charge? (If you mean multiple people, ask: Which members are in charge?)

Memory tricks and quick checks you can do in 5 seconds

Two fast checks fix most errors: the swap test and the statement test. If uncertainty remains, rephrase to name the subject explicitly.

Swap test: Replace who with he/she/they and use the verb that fits. He needs → Who needs.
Statement test: Turn the question into a statement. She knows the answer → Who knows the answer?
Plural clarity: If you mean multiple people, say "Which people" or "Which team members."

Swap: He knows the steps → Who knows the steps?
Statement: They decided yesterday → Who decided yesterday?

Hyphenation and spacing (brief)

Do not hyphenate who + verb (no who-know or who-knows). Place the question mark immediately after the sentence and use a single space after punctuation. Watch for misplaced apostrophes on verbs - these are common visual errors.

Never hyphenate who + verb.
Use standard spacing: "Who knows?" not "Who knows ?"
No apostrophes on regular verbs: knows (correct), know's (wrong).

Similar mistakes to watch out for

Common related errors include confusing who vs whom, adding apostrophes to verbs, and misusing collective nouns. Use substitution tests and explicit phrasing to fix them.

Who vs whom: use whom when the person is the object (Whom did you call?).
Apostrophes: don't use them to form verb endings (know's is wrong).
Collective nouns: if unsure about number, rephrase with "members" or use a singular verb in American English.

Wrong: Whom knows the answer?
Right: Who knows the answer?
Wrong: Who know's the plan?
Right: Who knows the plan?
Wrong: The team who want the trophy are excited.
Right: The team that wants the trophy is excited. (Or: The players who want the trophy are excited.)

FAQ

Is "who" singular or plural?

Who can be singular or plural. Substitute he/she (singular) or they (plural) to pick the correct verb form.

Should I write "who knows" or "who know"?

Use "who knows" for asking about one person's knowledge in the present. Use "who know" only if who clearly refers to multiple people; it's usually clearer to rephrase as "Which people know?"

Is "who's" correct for "who is" and "who has"?

Yes. "Who's" contracts "who is" or "who has" (Who's coming? / Who's finished?). It is not a possessive.

When should I use "whom" instead of "who"?

Use whom when the person is the object of a verb or preposition: Whom did you call? If the person performs the action, use who: Who called?

Why do people write "who know's" with an apostrophe?

They confuse apostrophes with verb endings. Apostrophes mark possession or contractions, not regular verb endings. The correct form is "who knows."

Still unsure? Quick fix before you send

If a who + verb sentence still feels wrong, run the swap and statement tests, or paste the sentence into the checker widget above for an instant rewrite. Small checks stop common slips in emails, reports and assignments.