So we've already discussed at length whether it's okay to start a sentence with a coordinating conjunction, and it's pretty clear that it is (and I've already done it in this sentence). But (there we go again) it's very common to start a sentence with a conjunction followed by a comma, like this:

So, here I go writing the first example.

This isn't limited to the beginning of a sentence. Although I've mostly seen it in the beginning of sentences, it's also common to see things like

I wrote the first example, and, then I wrote the second example.

The origin of this is pretty clear; it's the fact that we take often pause in such situations in spoken English, and people who see commas simply as punctuation sprinkled about to create pauses would never second guess putting a comma here.

It's my understanding that this is incorrect—that a comma should not follow a conjunction like this—but I don't have any definitive sources, so I wanted to make sure.

  • I don't really consider "I wrote the first example, and, then I wrote the second example" very good. I would actually take out both commas. – MrHen Jul 22 '11 at 4:42
  • @MrHen, you're right; the example is a bit too trivial to actually necessitate a comma between the independent clauses, but that specific example wasn't really the point. How would you feel about I wrote an extremely long-winded and complicated example that many people who don't really understand grammar would probably consider a run-on sentence, and then I wrote the second example which was somehow even more long-winded and complicated than the first.? – rubergly Jul 22 '11 at 6:45
  • All of the comments I'm seeing here seem to be leading to the conclusion that you would place the comma only after the conjunction in a scenario where a sentence interrupter immediately follows the conjunction. – monica Jul 31 '19 at 5:29
  • I’d advise you not to start a question with a coordinating conjunction because it is a carry-over from what many regard as sloppy speech and will make a poor initial impression with those people (including myself). Why antagonise your audience when you don’t have to? – David Jul 31 '19 at 19:24

I don't know if it is flat out "incorrect", but I do know many style manuals recommend against it.

When I was young, the rule used to be that you are supposed to use a comma between phrases (before the conjunction, not after) if there are more than two things so conjoined. If it is only two, the comma is optional. I'd usually leave it off. You'd only put a comma after the conjunction if there also happens to be a subjunctive clause inserted there.

I had an occasion to look at a more recent style guide, and I believe it said the comma before the conjunction is always optional. I don't have any guide with me right now, sadly.

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  • So given a sentence such as I could goto the park or I could goto the zoo it could be written as that AND as I could goto the park, or I could goto the zoo? – Chris Marisic Apr 28 '14 at 14:51
  • @ChrisMarisic - Technically neither, since "goto" is only a (key)word in programming languages. But if you change it to the English "go to", then yes either would be OK. Personally, I'd read the second as having a slightly larger pause between the phrases (presumably to emphasize the choices, rather than the overall fact of a choice). – T.E.D. Apr 28 '14 at 15:36
  • If the sentence wasn't a choice as that's so clearly defined in that example with the OR, would that be the place for a semicolon? Ironically I seemed to do exactly what I stated. "Would that question be better off as if the sentence wasn't a choice as that's so clearly defined in that example with the OR ; would that be the place for a semicolon?" Which is better? – Chris Marisic Apr 29 '14 at 17:14

It is incorrect in most situations, but there are some valid cases when the comma is fine: when it is used to isolate an interleaved sentence, to mark an interposition or to express a rhetorical pause.

Here is a phrase where the comma is not welcome:

So we decided to forgive them.

Our phrase starts with a conjunctive sentence and the so comes naturally first to introduce the conclusion. This is the conclusion of an implied debate that must have taken place some time in the past. The decision to forgive them (the second sentence) is the conclusion of that past debate. No commas here!

But let's introduce another sentence and make the debate explicit rather than implied:

So, after we discussed this at lengths, we decided to forgive them.

The sentence after we discussed this at lengths is interleaved with the sentence So we decided.... We use commas to separate it and, if we want to go even further, we can use paratheses: So (after we discussed this at lengths) we decided to forgive them.

The natural order of sentences would actually be:

So we decided to forgive them after we discussed it at lengths.

The commas can also be used in the same sentence when there's an interposition -- something that brakes the natural flow of speaking to bring some details but still is not a complete sentence:

So, after a long debate, we decided to forgive them.

The after a long debate is not a sentence, but just a detail the speaker is eager to emphasise.

In this case, the commas coincide with actual speech pauses. And again we may use paratheses, but this is a bit extreme and it implies longer speech pauses and a change of tonality as well.

There's another aspect of the "So, ..." -- a rhetorical one. In many cases, the speaker will say "So" and then make a long pause. This is usually used for thinking, introducing a threat etc.

 So, you thought you could outsmart us!


 "Where were you at the time of the crime?"
 "So, I went to the movies, Jenna and I... and then we went straight home..."

The rhetorical pauses are not necessarily correct from the grammar point of view, but they are useful to let the reader sense the speaker pauses after saying So. A more sophisticated writer would use a pause line — (— in HTML code) instead of the comma.

"So— you thought you could outsmart us!"

There's also the matter of the length of the pause. Comma is more recommended for shorter pauses and the — for longer, theatrical pauses.

When the comma would be utterly against grammar rules and the sentence flow in a phrase, the — must be used. Never write something like:

I wrote the first example, and, then I wrote the second example.

If the pauses have to be passed on to the reader do this:

I wrote the first example— and— then I wrote the second example.

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  • Good answer, but I have a quibble: Your final example with em dashes isn't any more grammatical than the equivalent answer with commas. All it does is change the feel of the sentence; an em dash has a more urgent, choppy feel than a comma when used in dialog. Which ungrammatical sentence one uses depends on the feel one is looking to convey. – Goodbye Stack Exchange Jul 25 '11 at 22:04
  • @Neil Fein: I think the I wrote the first example, and, then I wrote the second example won't be able to transmit the speech pauses to the reader because it looks too grammatically incorrect. The reader would only conclude you have a problem with commas rather than imagine the pauses. Writing something like that would look childishly incorrect and fail to send the message. If, on the other hand, the — implies a pause that's more dramatic than it's the case, I would try this: I wrote the first example... and... then I wrote the second example. – Neovibrant Jul 26 '11 at 7:55

"So" is also an adverb, and it's my understanding that this is the intent when used at the beginning of a sentence. If this is the case, it's the same as starting a sentence with any other adverb. I am fairly confident that you never follow a conjunction with a comma (and I'd argue that putting one before is probably in poor taste, but that's another discussion!).

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I have often used commas after conjunctions, but only because it is part of my personal style to often place a dependent clause directly following a conjunction. The placement of the comma helps to prevent reader confusion and seems natural as in speech.


  • Without commas: I was sick but because I had no money could not afford to go to the doctor.

  • With commas: I was sick but, because I had no money, could not afford to go to the doctor.

This makes sense because, if you take the dependent clause out of the sentence, there would be no need for commas:

  • I was sick but could not afford to go to the doctor.

Most grammar books and sites deter against placing a comma after a conjunction, stating that it is a commonly broken rule. Here is a similar example of what they consider to be an inappropriately placed comma:

  • Jimmy slammed the window but, Ida says it is not broken.

This makes sense, as it is a general rule that the comma would need to be placed before the conjunction placed between two independent clauses with different subjects (Jimmy/Ida).

Despite this, most of the same sources aforementioned have also sated that there are rare cases in which a comma would need to be placed after a conjunction. I am guessing the case I have previously stated would be one of the rare ones.

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