How to Use a Comma with “So”: Comma Before “So” vs Comma After “So”

Writing

15th August 2024

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using comma with so

The humble comma, despite being a small punctuation mark, plays a crucial role in shaping the clarity and flow of sentences. Its misuse or omission can easily alter the meaning of a sentence or create confusion. One of the most common challenges in comma usage arises when dealing with the word “so.” Whether you’re wondering if you should use a comma before “so” or are curious about the comma after “so” at the beginning of a sentence, this blog post is here to clear up any confusion. We’ll explore the rules and nuances of using a comma with “so,” complete with examples to illustrate each point.

Do You Use a Comma Before “So”?

One of the most frequently asked questions about comma usage is whether to place a comma before “so.” The answer depends on the role that “so” plays in the sentence.

1. “So” as a Coordinating Conjunction

“So” is often used as a coordinating conjunction, connecting two independent clauses. An independent clause is a group of words that can stand alone as a complete sentence. When “so” is used to join two independent clauses, a comma is needed before “so.”

Example:

  • Correct: “I was feeling peckish, so I decided to prepare a sandwich.”
  • Incorrect: “I was feeling peckish so I decided to prepare a sandwich.”

In this sentence, “I was feeling peckish” and “I decided to prepare a sandwich” are both independent clauses. The comma before “so” is necessary to indicate that these are two separate ideas being connected.

2. “So” as a Subordinating Conjunction or Adverb

However, “so” can also be used as a subordinating conjunction or adverb, meaning it doesn’t always require a comma before it. When “so” indicates purpose or consequence (often equivalent to “so that”), it’s not followed by an independent clause, and in such cases, a comma is typically not used.

Example:

  • Correct: “She whispered quietly so the baby wouldn’t wake up.”
  • Incorrect: “She whispered quietly, so the baby wouldn’t wake up.”

In this sentence, “so the baby wouldn’t wake up” is not an independent clause; it’s a dependent clause that explains the purpose of the whispering. Hence, no comma is needed before “so.”

Comma After “So” at the Beginning of a Sentence

Another common query is whether to place a comma after “so” when it starts a sentence. This depends on how “so” is being used.

1. “So” as a Conjunctive Adverb

When “so” is used at the beginning of a sentence as a conjunctive adverb (to summarise or conclude), it is often followed by a comma. This usage is quite common in formal writing.

Example:

  • Correct: “So, we’ve decided to extend the deadline by one week.”
  • Incorrect: “So we’ve decided to extend the deadline by one week.”

Here, “so” is summarising a previous point or decision. The comma after “so” is essential to indicate a brief pause and to separate the introductory word from the rest of the sentence.

2. “So” as a Simple Conjunction

When “so” is used as a simple conjunction at the beginning of a sentence to connect it with the previous idea (and not as a summary), it is generally not followed by a comma.

Example:

  • Correct: “So we waited for the storm to pass before leaving the house.”
  • Incorrect: “So, we waited for the storm to pass before leaving the house.”

In this sentence, “so” is directly connecting the result of an action. Placing a comma after “so” in this context would be incorrect because it would disrupt the flow of the sentence.

Comma After “So”: Examples and Clarifications

Understanding when to use a comma after “so” can be tricky, especially since the rules can vary depending on context. Below are some examples that illustrate correct and incorrect comma usage after “so”:

Example 1: “So” as a Conjunctive Adverb

  • Correct: “So, we’ve agreed to meet on Tuesday.”
  • Incorrect: “So we’ve agreed to meet on Tuesday.”

In this case, “so” is being used to introduce a conclusion or summary, hence the comma is required.

Example 2: “So” as a Coordinating Conjunction

  • Correct: “She was tired, so she went to bed early.”
  • Incorrect: “She was tired so, she went to bed early.”

Here, the comma is correctly placed before “so,” as it connects two independent clauses. There is no need for a comma after “so.”

Example 3: “So” Used in Speech or Informal Writing

  • Correct: “So, what’s next on the agenda?”
  • Incorrect: “So what’s next on the agenda?”

In conversational English or informal writing, “so” is often used at the beginning of a sentence to indicate a change in topic or to prompt someone. A comma after “so” in these contexts is generally correct and helps to convey the natural pause in speech.

Example 4: “So” in Compound Sentences

  • Correct: “He wanted to impress her, so he baked her favourite cake.”
  • Incorrect: “He wanted to impress her so he baked her favourite cake.”

When “so” connects two independent clauses in a compound sentence, always place a comma before it. The comma after “so” is not necessary unless the following clause is interrupted by additional elements such as interjections.

Common Pitfalls When Using Commas & Solution

The key to mastering the use of commas with “so” is understanding the function of “so” within the sentence. Here are some common pitfalls and tips on how to avoid them:

  • Misidentifying the Clause Type: A common mistake is failing to recognise whether “so” is connecting two independent clauses or if it’s being used as a subordinating conjunction. To avoid this, try splitting the sentence into two. If each part can stand alone as a sentence, use a comma before “so.”
  • Overuse of Commas: Some writers tend to overuse commas, placing them after “so” unnecessarily. Remember, a comma after “so” is only needed when “so” serves as a conjunctive adverb or in informal speech where a pause is naturally expected.
  • Inconsistent Usage: Be consistent with your comma usage, especially within the same piece of writing. If you start by using a comma after “so” when it begins a sentence, maintain this pattern throughout to avoid confusion.

Why Proper Comma Usage Matters

Using commas correctly is crucial for ensuring that your writing is clear and professional. Misplaced commas can lead to misinterpretations or a lack of clarity, which can detract from your overall message. When it comes to using “so” in your writing, understanding when to include a comma and when to omit it can make a significant difference in how your sentences are perceived.

Read also: How to Use the Oxord Comma and Understanding Comma Splices

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