if which (if, which)

Writers often type "if which" when the sentence needs either a condition (if) or a choice/relative clause (which). The two words do different jobs, so they shouldn't sit together as a fixed phrase.

Quick answer

Don't use "if which" as a unit. Choose one role: use If for a condition (think "in case") and Which to ask or point to a specific item ("which one?"). If a which-clause merely adds extra information, set it off with commas. If both meanings are needed, split or rewrite the sentence so each clause has a single job.

If = condition: If it rains, we'll cancel.
Which = asks or identifies a noun: Which candidate won?
Use commas for nonessential which-clauses: The report, which is long, needs editing.
When unsure: make a Which question, keep If and use a clear noun, or split the sentence.

Core explanation: conditional vs relative

If introduces a condition or hypothetical (if + clause). Which asks "which one?" or refers back to a noun (which + noun/clause). They perform different grammatical roles, so only one should lead the clause that performs that job.

Quick tests: Can you replace if with "in case"? If yes, keep if. Can you answer the clause with a noun or point to a specific item? Then use which. If both seem required, split the thought.

Wrong: If which candidate gets the most votes we'll proceed.
Right: Which candidate gets the most votes will determine who proceeds. Or: If one candidate gets the most votes, we'll proceed.
Wrong: If which report you meant wasn't attached, please resend it.
Right: Which report did you mean? If it wasn't attached, please resend it.

Punctuation & spacing: when commas matter

Missing or misplaced commas can make an If + which collision look accidental. A comma after if is rare and usually marks a parenthetical interruption: If, for whatever reason, ... . Which often needs commas when it adds nonessential information.

Don't add a comma after if just to separate it from which.
Set off nonessential which-clauses: The schedule, which changed this morning, is final.
If punctuation makes the sentence awkward, rewrite: split or rephrase the clause.

Wrong: If which is the correct answer, let me know.
Right: If that is the correct answer, let me know. Or: Which is the correct answer? Let me know.
Wrong: The design, if which you approve, will go live tomorrow.
Right: The design, which you approve, will go live tomorrow. Or: If you approve the design, it will go live tomorrow.

Hyphenation & spacing note

There is no hyphenation issue; this is a clause-role problem. Ensure proper spacing so words aren't accidentally joined (e.g., "ifwhich"). But the fix is usually rewriting, not re-spacing.

Check that "if which" appears as two words, but prefer a rewrite that removes the clash.
Avoid adding punctuation only to separate if and which-rewrite instead for clarity.

Grammar details: restrictive vs nonrestrictive which

Which typically introduces nonrestrictive (extra) information and uses commas. For essential (restrictive) information, prefer that or restructure the clause. If a clause is essential to identify the noun, rewrite so if doesn't sit next to which.

Nonrestrictive: The report, which arrived late, is on my desk.
Restrictive: The report that arrived late is the one I need.
If in doubt, rewrite: keep if with a clear noun, or start a which-question.

Wrong: If which data set shows the trend, we'll report it.
Right: If the data set shows the trend, we'll report it. Or: Which data set shows the trend?

Real usage and tone: work, school, and casual examples

Pick the pattern that fits your tone: ask Which for choices, keep If for conditions, or split the thought into two sentences.

Work:
Wrong: If which version should we send to the client please advise.
Right: Which version should we send to the client? Please advise.
Work:
Wrong: The timeline if which you agree will be attached.
Right: The timeline, which you agreed on, will be attached. Or: If you agree to the timeline, I'll attach it.
Work:
Wrong: If which mockup the team prefers we'll proceed.
Right: If the team prefers a mockup, we'll proceed. Or: Which mockup does the team prefer?
School:
Wrong: If which chapter covers photosynthesis is unclear ask now.
Right: Which chapter covers photosynthesis? Or: If the chapter that covers photosynthesis is unclear, ask now.
School:
Wrong: If which sources you cite affect your grade.
Right: Whether the sources you cite affect your grade depends on citation style. Or: If you cite these sources, your grade may improve.
School:
Wrong: If which hypothesis was tested it's not stated.
Right: If the hypothesis tested is not stated, the paper is incomplete. Or: Which hypothesis was tested?
Casual:
Wrong: If which movie do you want to watch.
Right: Which movie do you want to watch? Or: If you want to watch a movie, I'm in.
Casual:
Wrong: If which pizza toppings are okay tell me.
Right: Which pizza toppings are okay? Tell me. Or: If any toppings are off-limits, tell me.
Casual:
Wrong: If which friend will bring dessert is unknown.
Right: If you don't know which friend will bring dessert, ask the group. Or: Which friend is bringing dessert?

Try your own sentence

Test the whole sentence in context: decide whether it's asking "which?" or stating a condition. Then apply one of the three fixes below.

Examples: compact wrong → right pairs you can copy

Choose one pattern: make a Which question, keep If with a clear noun/pronoun, or split into two sentences.

Pattern A (Which?): Start a direct question with Which and drop if.
Pattern B (If + noun): Keep If and replace the which-clause with a clear noun or pronoun.
Pattern C (Split): Turn the sentence into two short sentences.

Wrong: If which of these speakers is available please tell me.
Right: Which of these speakers is available? Please tell me.
Wrong: Let me know if which version you prefer.
Right: Let me know which version you prefer.
Wrong: If which team wins the match I'll celebrate.
Right: If your team wins the match, I'll celebrate.
Wrong: If which task you mean is unclear ask now.
Right: If the task you mean is unclear, ask now. Or: Which task do you mean?
Wrong: If which file I should open is unknown tell me.
Right: If you're unsure which file to open, tell me. Or: Which file should I open?
Wrong: If which of the proposals is accepted we'll start.
Right: If a proposal is accepted, we'll start. Or: Which proposal was accepted?

Rewrite help: three fast fixes with extra examples

When you spot "if which," apply one of these three fixes: turn it into a Which question, make it a clear If + noun clause, or split into two sentences.

Fix A - Which question: Drop if, start with Which, add a question mark.
Fix B - Proper conditional: Keep If and replace the which-clause with a clear noun or pronoun.
Fix C - Split: Separate the choice and the condition into two sentences.

Original: If which meeting you meant was canceled please tell me. →
Rewrite: Which meeting did you mean? If it was canceled, please tell me.
Original: If which copy to print is unclear ask now. →
Rewrite: If it's unclear which copy to print, ask now. Or: Which copy should I print?
Original: If which candidates pass we'll hire two. →
Rewrite: If these candidates pass, we'll hire two. Or: Which candidates passed?
Original: If which data matters hasn't been decided. →
Rewrite: If it's undecided which data matters, let's decide now. Or: Which data matters?
Original: Let me know if which date fits. →
Rewrite: Let me know which date fits. Or: If that date fits, let me know.

Memory trick and quick rules

Mnemonics: If = In case. Which = Which one? Replace if with "in case." If the sentence still makes sense, it likely needs if. If you can answer the clause with "this/that/the X," use which.

Rule 1: If = condition. Test with "in case."
Rule 2: Which = asks or identifies a specific noun.
Rule 3: If both seem present, split the sentence so each clause does one job.

Similar mistakes to watch for

Fixing "if which" often means fixing nearby clause and comma issues too. Watch these related problems.

Which vs that: use that for essential info (no commas); which for extra info (commas).
If vs whether: whether introduces alternatives; choose the one that matches the meaning.
Comma placement: missing commas can create the illusion of an "if which" collision.

Wrong: The results which we expected were missing.
Right: The results, which we expected, were missing. Or if essential: The results that we expected were missing.
Wrong: I don't know if he will come or not whether he is invited.
Right: I don't know whether he will come. Or: If he is invited, I don't know whether he will come.

FAQ

Can I ever write "if which"?

Almost never. It signals a clash between a condition and a relative/choice clause. Instead, start a Which question, keep If with a clear noun, or split into two sentences.

When should I put a comma after if?

Only for a parenthetical interruption: "If, for any reason, the server fails, notify IT." Don't use a comma simply to separate if from which.

Is "which" acceptable after "if" in formal writing?

Avoid constructions where if and which collide. Rephrase so the conditional and the relative clause are distinct, or use that for essential clauses when appropriate.

How do I quickly fix a sentence that contains "if which"?

Ask: (1) Is it a question asking "which"? → Start with Which. (2) Is it a condition? → Keep If and use a clear noun/pronoun. (3) Is one clause extra? → Use commas or split into two sentences.

What search terms help me find more examples?

Search for patterns like "which vs that examples," "comma after if," or "fix if which sentence" to see rewrites and similar corrections.

Still unsure about a sentence?

Identify whether it's asking "which?" or stating a condition, apply one of the rewrites above, and read the result aloud. If it still feels awkward, split the idea into two sentences-the meaning will become clear.