I am not sure where I got the idea that a comma must be added before "so that", but I have been doing this for a while now, and now I realized it might be ungrammatical, or is it? When would you add a comma?

For example:

You should do several of the things that he asked you to do so that he doesn't blame you for his failure.

  • Punctuation is not about grammar. Period. – Robusto Mar 30 at 1:33
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    @frbsfok chompchomp.com/handouts/commatip07.pdf Your question made me read more on the issue. I deleted my answer because I wasn't confident enough about it. Please do look at the document I have linked to in this comment. – Don B. Mar 30 at 2:08
  • Why is that? I thought it was ok. – frbsfok Mar 30 at 2:17
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    @frbsfok I read about a possible exception, and I didn't want to tell you something that might mislead you. – Don B. Mar 30 at 2:40
  • grammar-quizzes.com/8-9.html – Khan Apr 24 at 12:37

You do not put a comma before "so that". Refer to this thread on wordreference, for example: https://forum.wordreference.com/threads/comma-before-so-that-conjunction-she-pulled-him-to-the-side-so-that.2974733/ Side note: The last two sentences seen in the first post are incorrect. A better way of writing those sentences are:

My pencil fell under my desk, so I couldn't see it.

George often told stories that weren't true, so no one believed him when he told about a deer in the school yard.

Commas go before the subordinate clause. "So that" pertains to a situation where someone does something in order to have an intended effect.

He told her a joke so that she could laugh.

I do agree that placing a comma in your example works for the sake of cohesion. However, it isn't correct, strictly speaking, in terms of grammar. It is up to you and whether you prioritize being a stickler for the oftentimes convoluted rules of the English language, or you prioritize your audience understanding you.


All languages have many rules; and they have also many exception, regarding grammar and punctuation. Sometimes the rules are necessary for obvious reasons, and other times they are just abstract conventions.

When judging how to write something, I follow the algorithm below:

  1. Is there a clear rule made for a good reason?
  2. Does it make sense to use one punctuation symbol or another? Or none? Make sense = is my message going to be understood clearer?
  3. If I break an (abstract / arbitrary) rule, in favor of clarity, will it "look" very bad?

I always try to follow the rules, but I keep in mind that, when communicating, the message that I want to convey is a lot more important than a rule made by some guy.

Also, I follow the algorithm above EVERY TIME when I write something, and need to decide what is better.

Going back your sentence, I had to read it several times in order to understand the sequence:

you to do so that he

Even if some rule tells that it is correct to NOT use a comma before "so that", I would gladly use a comma and break the rule (in this specific case), because it makes everything easier to read and understand - which is the ultimate purpose of the entire effort of communicating (writing).

Compare (the difference is one added comma in the second sentence):

You should do several of the things that he asked you to do so that he doesn't blame you for his failure.


You should do several of the things that he asked you to do, so that he doesn't blame you for his failure.

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    +1 for the focus on communication and getting one's point across – Elininja Apr 18 at 18:20
  • So you are talking about punctuations when misusing them yourself!? Your semicolon in the first statement should be a comma, and the dash is better stated as an Em dash (—). – Tasneem ZH Apr 18 at 18:30
  • @TasneemZH: again, you missed the point and misunderstood the explanations. Sorry. – virolino Apr 25 at 5:13
  • Don't worry, virolino. We are still learning. – Tasneem ZH Apr 25 at 9:15
  • @TasneemZH: here I agree 100% with you, we are still learning. E.g., I just learned something more about "to get sacked" a few minutes ago, from a colleague. – virolino Apr 25 at 9:20

The coordinating conjunction "so that" in the second clause is normally used to show the purpose of the action in the first clause. But it can also be used to show the result, effect, or consequence of the action stated in the first clause.

You don't put a comma before "so that" or so if it is used to indicate the purpose of the action in the first clause, but you can put a comma before the so or so that if it is used to show the result or effect of the action just stated.

Look at the following examples taken from various dictionaries, where a comma has been used before the "so that" that shows the result of the action just stated in the first clause.

He chopped the wolf's head from its body, so that it immediately died (Wikipedia).

He got up very late, so that he missed the bus (The Free Dictionary).

The gravestones were covered with most, so that it was impossible to read the names on them (Longman).

The birds return every year around March, so that April is a good time to see them (Cambridge).

The word "that" is optional in these examples. You can drop it, without any difference in the meaning.

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