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Comma After So: When Is It Applicable?

Chances are you’ve come across the Oxford Comma debate — there are some passionate perspectives on all sides. But that is not the only debate regarding commas. What about the use of the comma around the word “so”?

You may need a comma after “so” if it’s part of an introductory clause of a sentence, before a parenthetical statement, or as part of a parenthetical statement. When “so” is a conjunction at the start of a sentence, you will often use a comma after it. When “so” is an adverb, you rarely use a comma.

All of this may sound somewhat inconclusive and confusing, but you’ll see the rules (and the exceptions) to using the comma after “so” —  so keep reading.

Is There Always a Comma after So?

No, you do not always have to place a comma after “so.” In fact, when “so” is an adverb, there is rarely a comma after it. You’ll find that this occurs more often when “so” is a conjunction, but, even then, it does not apply to every situation. 

You’re more likely to encounter a comma before “so” rather than after it. This is because when “so” is a coordinating conjunction, it should have a comma before it:

  • I don’t like pizza, so I said I wasn’t hungry.

And if “so” is used as a subordinating conjunction, there is no comma at all.

  • I took her along so that she would stop complaining.

When Do You Put a Comma after So?

You mainly place the comma after “so” when it is a conjunction at the start of the sentence. However, bear in mind many people/teachers don’t like this in your writing. 

In general, formal/academic writing frowns on using conjunctions to begin a sentence, even though it is technically correct. This is because it can disrupt the flow of the writing and sound fragmented.

However, in limited circumstances, the adverb “so” can have a comma after it, too. 

The Chicago Manual of Style even affirms that in writing, a comma after “so” is unnecessary unless the statement that follows is a parenthetical statement or clause (source). 

Preceding a Parenthetical Statement

The following sentence will help demonstrate the use of a comma after “so” when it precedes a parenthetical statement:

So, despite his detractors, Piaget remains widely studied.

We’ll cover punctuating parenthetical statements in detail later in the article.

As Part of an Introductory Clause

Our next example shows the use of a comma after “so” when it’s part of an introductory clause.

He asked the teacher, “What will you do if Sam keeps misbehaving?”

“If so, I’ll send him home,” Mr. Edwards responded.

Here, the adverb “so” ends a dependent clause at the beginning of a sentence, so we follow the word “so” by a comma. Similar opening statements might include “maybe so” or “even so” that you would follow with a comma.

Using the Word “So” in Your Writing

The word “so” has multiple uses based on what part of speech it is, so you cannot apply a straightforward definition or rule to each and every case. 

Since we can’t get through each instance here, we’ll go through the most common ones. An important tip to remember before we begin is to check a dictionary if you ever question your usage. 

One of the most useful (and least boring) dictionaries available is The Oxford New Essential Dictionary — available on Amazon. It has various graphics and over 100,000 definitions for all of your defining needs. 

To start, the word “so” can be an adverb or a conjunction, so we’ll look at both uses next.


Grammarians refer to words that you use to modify a verb or adjective as adverbs (source). Adverbs change the meaning of the verb or adjective as they often provide direction (towards, above, etc.), manner (slowly, quickly, etc.), and time (never, tomorrow, sometimes, etc.).

Adverbs often take the form of an adjective +ly (quickly, greedily, zealously, etc.). However, the word “so” is not one of these.

As an adverb, the word “so” can indicate three things:

  1. A high degree
  2. Comparison/agreement 
  3. Repetition

Let’s break those down. The first indication above is that “so” represents a high degree of something, or, in simpler terms, it stands in place of the word “very.”

  • You are so pretty!
  • I don’t remember, to be perfectly honest; it was so long ago.
  • We have only so many books.

A second way you can use “so” is for comparison/agreement. In this way, “so” stands in place of “in the same way” or “in a similar way” (source).

  • I loved the book, and so did my sister.
  • He said, “I’m studying French.” She replied, “So am I.”

As you can see, a comma is unnecessary after or before the word “so” in this context.

You can prevent repetition using the word “so” as well. You’ll most often see this in questions. To give you an example, let’s say you’re asked, “Are you coming to tomorrow’s party?”

Sure, you can say “yes” or “no.” But often, you’ll naturally find yourself responding with a longer sentence. Saying ”No, I will not be coming to tomorrow’s party” sounds like a mouthful. Instead, you can respond with “No, I don’t think so.” 


“So” is often a coordinating conjunction, too, which means that “so” separates two independent clauses (source).

An independent clause always has a subject and a verb and can stand by itself (i.e., independently) because it expresses a complete idea. Consider the complete thoughts below:

  • She sat reading a book.
  • He was bored out of his mind.

When “so” is between two independent clauses, you must always use a comma before it. You’ll see an example below, but in this context, “so” can have two meanings:

  1. Therefore or thus
  2. In order that

First, “so” can stand in place of the words “therefore” or “thus.”

  • I have never been to the theme park, so I accepted her invitation.
  • He seemed smart, so I went along with his plan.

In each of these sentences, you’ll need to add a comma before “so” because it combines two complete thoughts with a comma and “so,” a conjunction.  

“So” can also stand in place of the words “in order that,” as you’ll see in the below examples. Note that here, too, you’ll need that comma with “so” to combine the two independent clauses.  

  • I told him the truth, so I didn’t get in trouble.
  • I hid my face so they couldn’t see my tears.

Subordinating Conjunctions

The word “so” can also be a subordinating conjunction, as in the second sentence. This means “so” connects an independent clause to a dependent clause.

When you use “so” in this way, the word stands in place of “so that.” In this context, “so” does not require a comma before or after:

  • I went to sleep early so I would wake up on time.
  • I go to school so I can learn.

Informally, you can use “so” as a question word or to refer to previous events/spoken words.

  • “I forgot to do my homework.” “So?”
  • So, that was interesting…”

This is something you encounter more in speech than in writing because the word can sound natural verbally — and at times be a filler word — but it is out of place in any piece of academic writing.

Some Essential Rules for Commas

Commas have many uses, but the most relevant for our purposes would be to connect independent clauses with a conjunction, set off introductory statements, and set off parenthetical statements (source).

Coordinating Conjunctions and Commas

Grammarians refer to the type of conjunctions that connect independent clauses as coordinating conjunctions. There are seven coordinating conjunctions, including “so”:


An easy way to remember these is the F.A.N.B.O.Y.S acronym.


A comma comes before a conjunction between two independent clauses. For example:

  • She was a good baker.
  • Her cake failed to impress.


  • She was a good baker, but her cake failed to impress.

At times, you may choose not to put a comma in if the sentence is very brief. Regardless, it is always acceptable to use a comma before a coordinating conjunction separating two independent clauses. In that sense, it’s safer to use it to avoid errors in your writing.

But be wary of comma splice problems. A comma splice error is when you join two independent clauses with a comma. Such as:

  • I read her book, it was a very entertaining book. 
  • Tomatoes are not vegetables, they are fruit.

These sentences may sound correct, but you cannot combine two independent clauses with a comma alone. You can fix the above errors by including a coordinating conjunction, swapping the comma for a semicolon, or creating two separate sentences.

Introductory Elements and Commas

You can use commas after an introductory element as well. This includes any sentence that introduces an idea or an exclamation. For example:

  • Once, there was a princess who lived in a Jade palace.
  • Wow, you really are something!
  • Even so, I thought the event went well.

Commas can also separate a quote from the rest of a sentence.

  • I told him, “You’ll never make any friends if you keep scowling that way.”
  • “You’re going to be okay,” Sarah said comfortingly, “You’re safe here.”

But not every quote requires a comma. For example, if a sentence merges into a quote, adding the comma can make your sentence sound clunky. 

  • The article argued that “Pizza is a far better source of nutrients than broccoli.”
  • He screamed “ouch!” when his leg made contact with the hardwood table.

Parenthetical Statements

Another way you can use a comma is for a parenthesis. A parenthesis is when there is a part of a sentence that interjects extra information. If you remove that part from the sentence, the sentence will still make sense.

A variety of punctuation marks can show a parenthesis, and you can use parentheses (round brackets) for this purpose.

  • He loved cakes (specifically, cheesecakes) more than he loved his entire family.

Another way to show parenthesis is through dashes:

  • He loved cakes — specifically, cheesecakes — more than he loved his entire family.

Remember that dashes are different from hyphens. If you want to learn more about hyphens, look at the article “High Quality or High-Quality: Understanding When to Use a Hyphen.”

Parenthetical Statements Using Commas

The final and most relevant way we’ll go over how to show parenthesis is through using a comma:

  • He loved cakes, specifically cheesecakes, more than he loved his entire family.

If you remove the words in between the brackets and the sentence still makes sense, you can conclude that the commas show a parenthesis.

Consider the following examples and whether they both make sense:

  1. The bestselling book series of all time, written by JK Rowling, is Harry Potter.
  2. The actress, and her best friend, were known for being rude to waiters.

Now try reading them with the parenthetical statement removed:

  1. The bestselling book series of all time is Harry Potter.
  2. The actress were known for being rude to waiters.

Only sentence one makes sense, and sentence two should not include the commas because the enclosed information is essential to understanding the sentence (so it’s not a proper parenthesis).

Parenthetical Comments and So

Looking at the word “so” specifically, you may find it attached to or within the parenthesis. “So” can stand on its own ahead of a parenthetical statement, which is the correct usage according to the Chicago Manual of Style:

  • So, one by one, the kindergartners lined up outside the classroom.
  • So, without hesitation, I jumped across the ledge.

“So” can also fall within parenthetical statements:

  • She agreed with him, unpleasant as it was to do so, to keep the peace.
  • “In this letter Prince Andrew pointed out to his father the danger of staying at Bald Hills, so near the theater of war and on the army’s direct line of march, and advised him to move to Moscow.” — extract from War and Peace (source).

“So,” at times, also comes after parenthetical statements:

  • She was friendly, pretty much a real-life angel, so I wasn’t scared to go to her for help.
  • I appreciated my friend, especially after he stayed up all night, so I baked him some cookies.

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Potentially, you can see a comma after “so” when it comes before parenthetical statements or at the end of one.

Final Thoughts

You’ll only have to have a comma after “so” when a parenthetical comment follows or when “so” is at the end of an opening clause or parenthetical statement.

As always, when it comes to grammar, things are not always as difficult as they look, and practice makes perfect. Because, when it comes to using a comma before “so,” you’ll find it’s often easy to identify based on whether “so” is an adverb or conjunction and where you’ve positioned it in your sentence.