Are both of the following sentences correct?

a: You can call me, if you need me. OR
b: You can call if you need me.

Note that in a:, the comma is placed before the "if" and is not present in case b.

From this link, I gather that it isn't necessary because it's a short sentence: Is it mandatory to use a comma before a coordinating conjunction uniting the two independent clauses in a compound sentence?

But can someone point out an "official" source on this usage?

  • @Simchona's answer is excellent, so I'll only note: In option a, the comma is somewhat disruptive when saying the sentence, where as in simchona's two examples where the subordinate comes at the beginning, there is no such disruption...the sentence just seems to flow off the tongue in a natural way.
    – jrista
    Aug 14, 2011 at 3:13

3 Answers 3


The question that you brought up wouldn't address your question because "if" is not one of the coordinating conjunctions, but it is a subordinating conjunction. The words that introduce each are:

Coordinating Conjunctions: and, but, or, yet, for, nor, so (a helpful acronym is FANBOYS)

Subordinating Conjunctions: after, although, as, as if, as long as, as though, because, before, even if, even though, if, if only, in order that, now that, once, rather than, since, so that, than, that, though, till, unless, until, when, whenever, where, whereas, wherever, while

The definition of a subordinating conjunction is:

Subordinating Conjunction (sometimes called a dependent word or subordinator) comes at the beginning of a Subordinate (or Dependent) Clause and establishes the relationship between the dependent clause and the rest of the sentence. It also turns the clause into something that depends on the rest of the sentence for its meaning.

He took to the stage as though he had been preparing for this moment all his life.

Because he loved acting, he refused to give up his dream of being in the movies.

Unless we act now, all is lost.

This article from Purdue on coordinating and subordinating conjunctions explains the usage of the subordinating conjunction as follows:

Notice that when the subordinate clause comes at the beginning, it’s necessary to insert a comma.

From this, the correct punctuation of "You can call me if you need me" is:

You can call me if you need me.

If you were to move the subordinating conjunction to the beginning, however, you would need the comma as follows:

If you need me, you can call me.


As in many other aspects of the English language this is an area where British and American usage reveal differences. The trend in British English writing is towards lighter internal sentence punctuation. (The Oxford comma is a case in point.) It is common to omit the comma even when the dependent/subordinate clause begins the sentence.

  • If the police had reacted more decisively the riots would not have spread.

Of course, there are times when comma omission will result in momentary ambiguity and is to be avoided:

  • While I was cooking my daughter did her homework.

As to official rules on comma use to separate clauses, there are none (unlike in German for example where the comma is mandatory between dependent and independent clauses regardless of where the clauses are placed.)

The previous sentence is an example of the light punctuation that I as a British writer prefer but which would seem careless to some American readers.

  • Are the then-clauses in a conditional sentence independent clauses, or do conditional sentences not have any independent clause? May 7, 2020 at 21:54
  • @HeWhoMustBeNamed. Yes, the 'then' clause (called the apodosis) is the main or independent clause in a conditional sentence.
    – Shoe
    May 8, 2020 at 11:04
  • Thanks, but how can we tell? And what function does the 'then' perform there, if not subordinating the consequent clause (And I'm not even clear why the 'then' wouldn't be considered a subordinating conjunction there)? // I do know that we can move around 'then' in the middle or to the end of the apodosis, so in that respect it's different from the subordinating conjunctions, but, nevertheless, its function seems to me to be complementary and parallel to that of the 'if', so that they seem to form part of a correlative conjunction, like "not only ... but also" and. . . May 12, 2020 at 11:48
  • [cont.] "either ... or". But whether they're actually a correlative conjunction or not, the function of 'then' seems to be at least similar enough to that of the 'if' to be recognised as a subordinating conjunction, too... But I would really like to know what all I'm missing here. May 12, 2020 at 11:48
  • @HeWhoMustBeNamed. Are you asking about all apodosis clauses or only those starting with then?
    – Shoe
    May 12, 2020 at 13:45

Both are correct. The implied nuances (perhaps rather overstated) are (a) "You can call me, if you need me [or even if you just want a chat]" and (b) "You can call me if you need me [but please don't bother me for some trivial reason]".

  • how are those two different?
    – P. Vowk
    Feb 28, 2017 at 16:09
  • @P.Vovk: Omitting the comma makes the condition ("if you need me") essential. The comma induces a slight separation of the condition, which softens it. To see this more clearly, consider stronger punctuation: "You can call me—if you need me". That implies "you can call me" (unconditionally), with the force of "if you need me" reduced to suggesting one occasion but not excluding others. Feb 28, 2017 at 17:06
  • According to The Chicago Manual of Style (16th ed), this is the only correct answer. The deciding factor is whether the dependent clause is restrictive (version b) or not (version a). Oct 2, 2017 at 3:46
  • The "if you need me" clause doesn't seem to me as acting to suggest one occasion without excluding others, as you note in a comment. Rather, to me it just seems like an explanation for why the person you're speaking to would call you, like in the comma-less version, but as a separate idea. Can you (or @BijouTrouvaille, who agreed to your answer) elucidate the meaning you're claiming it indicates within a context? Jan 30, 2020 at 15:19

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