There are many questions here about the use or placement of a comma.

The general rule I learned decades ago was that commas always appear in pairs, never by themselves.
Commas at the beginning of a sentence or next to other punctuation are omitted.

It's a very simple rule that almost always works (the serial comma is a corollary).

Is this rule no longer taught?

While it's handy for verifying correct usage, this rule is much more useful as a means of detecting incorrect usage.

If there is a comma that can't be paired using this rule, it's almost certain that the comma shouldn't be there, or that another comma needs to be added elsewhere.

  • 2
    That’s funny Reread your rule…
    – Jim
    Aug 6 at 5:32
  • @Jim, if you're referring to the comma in my second sentence, reread the following sentence. ",never by themselves" is actually ", never by themselves," which produces ",." at the end, which becomes ".". Aug 6 at 14:14
  • 1
    Ok, you’ve concocted a way to turn every single-comma’d sentence into one with a second invisible comma.
    – Jim
    Aug 6 at 15:21
  • @Jim. That aspect confirms that the commas are okay. But it's more useful when there is a missing or extra comma. Being unable to play this matching game means that something is wrong. ¶ Consider: Loyalty gave way to desire and Garrett, the turncoat told Sherry what I was up to., where one can't pair the comma. Or see my answer to Is a comma needed after "a, b and c"? Aug 6 at 16:44

1 Answer 1


No. If you learned that decades ago, then you learned something incorrect. The prior sentence contains a perfect example of commas not always appearing in pairs. It's quite common for commas to not appear in pairs, probably even more common for them not to.

A few examples of when you do see commas appearing in pairs include when such things appear mid-sentence as:

  • parenthetical words, phrases, and clauses (e.g., "Sam, crying, held me.")
  • vocatives (e.g., "I don't know, Ray, but I'll find out for you.")
  • appositives (e.g., "That boy over there, my brother, is up next.")
  • nonrestrictive clauses (e.g., "The shirt, which was his dad's, was way too big for him.")

Several examples of when you don't see commas appearing in pairs include:

  • introductory modifiers (e.g., "Sadly, I won't be able to attend.")
  • coordinate clauses (e.g., "I hate coming here, yet here I am again.")
  • subordinate clauses (e.g., "If you build it, they will come.")
  • absolute phrases (e.g., "Tom left, his jaw still smarting from Jack's punch.")
  • dates (e.g., "March 10, 1970 is when he was born.")
  • places (e.g., "Albany, New York is where the conference is being held.")

What appears between paired commas is most often nonessential information or not critical to the operation of the sentence, meaning you could pluck it out of the sentence and have the sentence still be completely grammatical and operational, just with a bit less information, information that is likely extraneous or trivial.

So, in short, there are situations in which commas are used in pairs, but it is not now nor has ever been a "general rule," as you put it, that "commas always appear in pairs, never by themselves."

  • I see the "Albany" and "March" cases simply as examples of conventions for writing dates and addresses (hence my "almost always"). Commas inside numbers would be another example. They are not there for grammatical purposes. ¶ There's a deleted comma before "Sadly" and after "punch". (e.g. "[I'm busy tomorrow, so] sadly, I won't …"). ¶ The "build it" and "yet again" commas are either unnecessary or should be a long dash (to indicate a meaningful pause). Aug 6 at 14:51
  • "That's a baseless and false claim." ??? That numbers are written as ##,###,###.## is a convention, not a rule of grammar. In France it would be "##.###.###,##", in India it's "#,##,##,###.##". ¶ "Corollary" means that the serial comma rule is a consequence of my rule, not a proof of it. ¶ “example: the comma after "say."”. The comma isn't after "say", it is before the quotation. That quotation ends at a period, but if something else had come after the quotation, it would require a matching comma after the quotation. Aug 6 at 22:33
  • We seem to be talking completely different languages. ¶ "neither you nor I were talking about how commas are used in numbers in mathematic expressions", yet in my very first comment I said "Commas inside numbers would be another example. They are not there for grammatical purposes.". ¶ “that's not what "corollary" means”. But it is. A corollary is something that naturally follows from the original rule. As in "A and B" → "A (B) and C "→ "A (B) (C) and D" → … , with the parentheses replaced by commas, producing "A, B, C, and D. The serial comma after the "C" is required by "my" rule. Aug 7 at 0:48
  • If you really want to disprove this rule, rather than arguing with me, simply provide examples of misplaced commas that the rule will fail to detect (keeping in mind that there is an implied comma at the beginning and end of every sentence). Aug 7 at 1:19

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