Comma Before or After So | Correct Use & Examples
You need a comma before the conjunction “so” when it could be replaced with “therefore” (i.e., “for that reason”).
I was tired. Therefore, I went to bed.
Tom left early so that he could arrive at the office on time.
When “so” is used as an adverb, pronoun, or other part of speech, commas are generally not needed (e.g., “I hope so,” “he stayed a week or so,” “there’s still so much to do”).
When to use a comma before so
You should put a comma before “so” when it’s used as a coordinating conjunction to connect two independent clauses. A clause is independent if it contains both a subject and a verb and expresses a complete thought. When used in this way, “so” means “therefore” or “for this reason.”
To check whether “so” is being used in this way, try substituting it with “so that” and “therefore” to see which one more closely fits your intended meaning. For instance, consider the sentence “Jane was tired, so we rescheduled.”
When “so” is replaced with “so that,” the sentence lacks coherence, seeming to suggest that Jane’s tiredness was a deliberate tactic to make us reschedule:
- Jane was tired so that we rescheduled.
When “so” is replaced with “therefore,” the sentence conveys the correct meaning (albeit in a more formal style).
- Jane was tired. Therefore, we rescheduled.
In this context, “so” is acting as a coordinating conjunction and a comma is needed before it.
When you don’t need a comma with so
You don’t need a comma before “so” when it’s used as a subordinating conjunction to connect an independent clause with a dependent clause (i.e., a clause that does not express a complete thought). When used in this way, “so” is a synonym for “so that.”
To check whether “so” is being used in this way, try replacing it with “therefore” and “so that” to see which one fits the intended meaning. For instance, consider the sentence “I studied hard so I could pass the test.”
When “so” is replaced with “therefore,” the sentence makes sense, but it is unlikely to reflect the original meaning.
- I studied hard. Therefore, I could pass the test.
When “so” is replaced with “so that,” the sentence accurately conveys the intended meaning: that the speaker studied hard in an effort to pass.
- I studied hard so that I could pass the test.
In this context, “so” is acting as a subordinating conjunction and no comma is needed before it.
When to use a comma after so
When “so” is used as a coordinating conjunction or subordinating conjunction, there’s generally no need to put a comma after it.
This is the case even when “so” appears as a conjunction at the start of a sentence.
- It was late. So, I went to bed.
- It was late. So I went to bed.
When “so” is used as an interjection, a comma is optional. You can include one to express a natural pause in the sentence.
- So, how are things?
- So I’ll talk to you soon.
A comma should also appear after “so” when it is followed by an interrupter (i.e., a parenthetical expression that adds emphasis or qualifies a statement). In these instances, a comma should also appear after the interrupter.
There’s room in the bus, so, if you like, you can join us.
Quiz: Comma before or after so
Test your knowledge about when to use a comma before or after “so” with the worksheet below. Add commas wherever you think they are needed. Some sentences do not require a comma.
