Learn English – When do we need to put a comma after “so” at the beginning of a sentence

commasconjunctionspunctuation

I noticed that most of the times when the conjunction "so" is used at the beginning of a sentence, it is followed by a comma:

So, this gets published but the fact that it is inaccurate gets moderated out.

Occasionally, I find sentences with no comma after "so":

So he went to Ishmael and married Mahalath.

I am guessing that whether to put comma or not after the "so" conjunction is related to the context and emphasis rather than to the sentence structure, but I am unable to pinpoint it out.

So when do we need to put comma after "so"? (← Do I need a comma after the "so" here?)

P.S.: I know there is another usage of "so" as an adjective or an adverb, in which case no comma is necessary, for example: "So big is the caravan that it cannot fit into the garage."

P.S.: I did skim through the list of questions with [comma] tag, and found no question on this conjunction yet.

Best Answer

So, now that you've asked this question, how can we answer it? "So," suggests a substantial turning point in the discourse, for example between describing a situation and reacting to change it. See Fattie's answer for good examples where the turning point is substantial because of the outrageousness of the situation. Less outrageous examples still have a substantial turning point:

As my students, you have worked hard and studied carefully. So, today it's time to party!

So now let me describe "So" without a comma. "So" suggests logical continuity, for example between describing a situation and its usual result. When possible, it would often be better to combine a "So" sentence with the preceding sentence.

As my students, you have worked hard and studied carefully. So I know you will pass the examination.

As my students, you have worked hard and studied carefully, so I know you will pass the examination.