The comma goes before “but,” never after it. Write “I called twice, but nobody answered,” not “I called twice but, nobody answered.” The second version is always wrong, and it is the single most common punctuation error people make with this word.
There is one situation where a comma legitimately appears after “but,” and it has nothing to do with the conjunction itself. That case, plus the times you should drop the comma entirely, is what the rest of this covers.
The Rule: Comma Before “But” Joining Two Sentences
“But” is a coordinating conjunction. When it joins two independent clauses, two word groups that could each stand alone as a sentence, a comma goes before it. Purdue OWL’s comma rules list this first for a reason: it covers the majority of real cases.
- “The recipe called for basil, but I used oregano.”
- “She apologized, but the damage was done.”
- “We can leave now, but the traffic will be worse.”
Test each half. “The recipe called for basil” is a sentence. “I used oregano” is a sentence. Two sentences joined by “but” means the comma stays.
When You Don’t Need a Comma Before “But”
If what follows “but” cannot stand alone as a sentence, leave the comma out. This usually happens when the two halves share a subject and the second half is only a verb phrase or a fragment.
- “She apologized but never explained why.” (No second subject, no comma.)
- “The soup was cheap but delicious.” (Two adjectives, not two clauses.)
- “He tried but failed.”
Compare the pair directly: “She apologized, but she never explained why” takes the comma because “she never explained why” is a full sentence; “She apologized but never explained why” drops it because “never explained why” is not.
Very short clauses are the one judgment call. “I was tired but I stayed” is acceptable without a comma in informal writing, since both halves are tiny and the meaning is unmistakable. In anything formal, keeping the comma is never wrong.
The One Case Where a Comma Follows “But”
A comma appears after “but” only when an interrupter comes next, and it always arrives in a pair that brackets the interrupting phrase:
- “I wanted to help, but, honestly, I had no idea where to start.”
- “We booked the flight, but, as it turned out, the meeting moved.”
- “He agreed, but, unlike last time, he asked for it in writing.”
Notice that the comma after “but” is not punctuating the conjunction at all; it is opening a parenthetical, and a matching comma closes it. Remove the interrupter and the extra commas go with it: “I wanted to help, but I had no idea where to start.”
Because that stacking looks cluttered, many editors rewrite instead: “Honestly, I wanted to help, but I had no idea where to start.” If you find yourself with three commas in ten words, moving the interrupter is usually the better fix.
The Two-Second Test
Cover everything before “but” with your hand and read what is left. If it works as a complete sentence on its own, put a comma before “but.” If it does not, leave it out. That single check resolves nearly every case without any grammar vocabulary.
A second check catches the error in the title of this page: never place a comma directly after “but” unless the very next words are a phrase you could lift out of the sentence entirely. “But, nobody answered” fails that test, which is why it is wrong.
Starting a Sentence With “But”
Beginning a sentence with “but” is grammatically fine and has been standard in published English for centuries, despite what many of us were taught in school. It does not take a comma after it: write “But nobody answered,” not “But, nobody answered.”
The exception is the same as above. “But then, nothing about that week went to plan” and “But, to be fair, she warned us” both contain interrupters, not a comma attached to “but.”
Same Question, Other Words
The related searches for this question are really one question asked about different words, and the answers split into two groups.
| Word | Type | Comma before? | Comma after? |
|---|---|---|---|
| but, and, so, or, yet | Coordinating conjunction | Yes, when joining two independent clauses | No |
| because | Subordinating conjunction | Usually no; add one only to prevent misreading | No |
| however, therefore, moreover | Conjunctive adverb | Semicolon or period before | Yes, comma after |
| for example, that is, such as | Transitional phrase | Yes | Yes |
| which, who, whom | Relative pronoun | Yes, when the clause is removable | Yes, if the sentence continues |
That last row is where “but” and “however” part ways, and it explains why writers who apply the “but” rule to “however” end up with comma splices. “However” needs a semicolon or a full stop before it: “I called twice; however, nobody answered.” The same bracketing logic applies to transitional phrases, which our guide to commas with “for example” works through in detail.
FAQ: Comma Before or After “But”
Where exactly do you put the comma with “but”?
Put it immediately before “but” and never directly after it: “It rained, but we went anyway.” The comma belongs to the clause that ends, not to the conjunction that starts the next one.
What is the “3 comma rule”?
There is no official three-comma rule in English punctuation; the phrase usually refers to informal summaries of the three commonest uses: separating items in a list, setting off introductory elements, and joining independent clauses with a coordinating conjunction like “but.”
What are the main rules for commas?
The standard set covers lists, coordinating conjunctions joining clauses, introductory words and phrases, non-essential information, direct address, dates and addresses, quotations, and coordinate adjectives. Purdue OWL’s extended comma rules lay all of them out with examples.
Is it “Happy birthday Name” or “Happy birthday, Name”?
“Happy birthday, Sarah” is correct. A name used to address someone directly is set off by a comma, which is the direct-address rule, unrelated to conjunctions but a frequent source of the same uncertainty.
If you remember one thing: the comma leans backward. It closes the clause that came before “but,” which is why it never sits on the other side.
