Does the Comma Go Before or After “So”?

Oh, commas. The bane of every writer’s existence. The comma is a small but mighty punctuation mark that can make a big impact on your writing. So, does the comma go before or after “so?” Don’t let my previous sentence fool you. “So” bends some of the grammar rules you may be familiar with, so let’s discover when to use a comma with “so.”

Do Commas Go Before or After “So”?

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Depending on the context, “so” can be used as a coordinating conjunction, a subordinating conjunction, an adverb, or even when introducing a parenthetical expression or parenthetical components. Identifying what role “so” plays in a sentence is key to determining when to use a comma with “so.”

But it depends on the entire phrase. To answer this question, we must first talk about independent clauses. This goes for even basic sentences.

In grammar, independent clauses are sentences that can stand on their own and express a complete thought. Some might say they create original sentences and do it differently for stylistic reasons. But there are actually common rules you should follow when writing complete sentences with commas. 

For example, you could have phrases such as “Pam didn’t make it in time for dinner, but Camille enjoys having dinner on her own.”

Each of these two sentences, separated by the coordinating conjunction “but,” could stand on its own.

“So” is a coordinating conjunction (just like “but”), so when we use it to connect two independent clauses, you always add a comma before it.

Sentence examples with a comma before “so”:

  • My laptop broke, so I had to buy a new one.
  • It was a really warm morning, so Kayla decided to go jogging.

However, “so” can also be the first word of a parenthetical expression, in which case the comma goes after it.

Examples:

  • We were fighting so, in the heat of the moment, I might have said some things I regret.
  • I don’t want to waste my time so, if you’re serious about this, call me.

You also use a comma after “so” at the beginning of a sentence.

Examples:

  • I want to know more about you. So, what have you been doing lately?
  • So, even though I’m angry, I’ll give you one more chance.

Times When You Must Not Use a Comma

“So” is not always used with a comma. As mentioned earlier, “so” can be a coordinating conjunction that connects two independent clauses. However, there are cases where “so” connects an independent and a dependent clause, in which case it turns into a subordinating junction.

You don’t use a comma with “so” when this happens.

Let’s look at an example. Suppose you’re waiting for your mother to come home with the groceries because you’re starving. It’s running late, so you decide to order some food.

That leads to the statement, “I ordered a pizza when my mom was late.”

In this particular statement, “when my mom was late” is not a sentence that could stand on its own. That makes it a dependent clause. When dealing with dependable clauses, never use a comma with “so.”

Let’s look at some examples:

  • I wanted to buy a car so I could travel more with my family.
  • You lied to your mom so you could go to the party.

Substituting a Coordinating Conjunction

In certain cases, it might be difficult to tell if “so” is a coordinating conjunction and is, therefore, complicated to know whether or not you should add a comma before it. Here is a little trick to help you out.

If you can replace “so” with “therefore” in a sentence, and it would still make sense, “so” is a coordinating conjunction.

Let’s take an example from above and see how that works:

  • My laptop broke, so I had to buy a new one.
  • My laptop broke, therefore I had to buy a new one.

The second sentence would make complete sense even if we substituted the coordinating conjunction “so” with “therefore.”

Substitution of Subordinating Conjunction

When “so” is used as a subordinating conjunction, you can add “that” after it, and the sentence would still make sense.

For example:

  • You lied to your mom so you could go to the party.
  • You lied to your mom so that you could go to the party.

Even after adding “that” after “so,” the sentence makes complete sense. That’s how we know “so” is being used as subordinating conjunction and doesn’t require adding a comma before it.

So As a Conjunctive Adverb

When “so” can be replaced with “therefore,” it means it’s a conjunctive adverb. The role of a conjunctive adverb is to connect two independent clauses in a sentence.

Consequently, you must always use a comma or a semicolon before “so.”

Examples:

  • I partied the entire weekend; therefore, I didn’t study for the test on Monday.
  • I partied the entire weekend, so I didn’t study for the test on Monday.

So Preceding a Parenthetical Expression

A parenthetical expression is an addition to a sentence that doesn’t change its meaning but can add some extra information to the phrase.

Examples:

  • The test on Monday, which is worth half of my final grade, wasn’t that difficult.
  • Susan (who wasn’t thrilled about meeting Paul) decided to wear something casual.
  • Some Eastern European countries – like Bulgaria or Romania – are not part of the Schengen zone.

“So” isn’t very commonly used before a parenthetical expression, but when we do use it, it’s usually preceded by a comma, parentheses, or dashes.

Examples:

  • Kelly was bored (so bored that she wasn’t paying attention in class) and never wanted to be part of the debate.
  • Wear a protective mask when using spray paint – so you can avoid inhaling fumes – and always follow the manufacturer’s instructions.

Bottom Line

To sum it up, “so” can serve many different roles in a sentence, so you must identify that role before determining whether or not you can use a comma and where it should be placed. So, are things clearer now? I hope my guide helped you!

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