Is There a Comma Before “Then”?

Understanding when to use a comma before “then” can be tricky but essential for clarity and flow in writing. This guide will break down the rules for using commas with “then,” providing correct and incorrect examples to illustrate each point.

When to Use a Comma Before “Then”

Rule 1: Sequence of Events

Correct Usage:

• First, we will gather data, then analyze it.
• We washed the dishes, then dried them.

Incorrect Usage:

• First, we will gather data then analyze it.
• We washed the dishes then dried them.

Explanation: A comma before “then” helps separate steps in a sequence of actions, especially when “then” serves to introduce the next step.

Rule 2: “Then” at the Beginning of a Sentence

Correct Usage:

• Then, we decided to return home.
• Then, the weather cleared up.

Incorrect Usage:

• Then we decided to return home.
• Then the weather cleared up.

Explanation: When “then” starts a sentence to continue narration or a series of events, it’s often followed by a comma for clarity and pacing.

Rule 3: “Then” as an Afterthought

Correct Usage:

• We need to finish by Tuesday, then.
• You’re going to pay for the tickets, then.

Incorrect Usage:

• We need to finish by Tuesday then.
• You’re going to pay for the tickets then.

Explanation: A comma before “then” can indicate that “then” is being used as an afterthought or to confirm a decision or understanding.

Read More: Is There a Comma Before “Instead”?

Rule 4: Independent Clauses Connected by “Then”

Correct Usage:

• She studied hard for the exams; then, she passed with flying colors.
• The sun set; then, the stars appeared.

Incorrect Usage:

• She studied hard for the exams then, she passed with flying colors.
• The sun set then, the stars appeared.

Explanation: Use a semicolon before “then” when connecting two independent clauses, followed by a comma, to indicate a chronological sequence or result.

Rule 5: “Then” for Comparison

Correct Usage:

• If you prefer chocolate over vanilla, then, by all means, choose chocolate.
• You said it was too expensive; then, you bought it anyway.

Incorrect Usage:

• If you prefer chocolate over vanilla then by all means choose chocolate.
• You said it was too expensive then you bought it anyway.

Explanation: A comma can be used before “then” to emphasize a contrast or decision in comparative structures.

Rule 6: Avoiding Commas for Immediate Actions

Correct Usage:

• Turn left then go straight.
• Finish your homework then you can watch TV.

Incorrect Usage:

• Turn left, then go straight.
• Finish your homework, then you can watch TV.

Explanation: When actions or instructions are immediate and directly connected, a comma before “then” is not necessary.

Rule 7: “Then” in Conditional Sentences

Correct Usage:

• If you’re hungry, then we should start cooking.
• If it rains, then we’ll have to cancel the picnic.

Incorrect Usage:

• If you’re hungry then we should start cooking.
• If it rains then we’ll have to cancel the picnic.

Explanation: In conditional sentences, a comma before “then” can help separate the condition from the result for better readability.

Rule 8: Emphasis or Clarification

Correct Usage:

• You claim to be an expert; then, prove it.
• You want to leave early; then, make sure all your work is done.

Incorrect Usage:

• You claim to be an expert then prove it.
• You want to leave early then make sure all your work is done.

Explanation: Use a comma before “then” to add emphasis or demand action, especially after a challenge or command.

Rule 9: Lists or Series

Correct Usage:

• First, make the dough; next, let it rise; then, bake it.
• We’ll discuss the budget, review the project timeline, then finalize the plans.

Incorrect Usage:

• First make the dough, next let it rise, then bake it.
• We’ll discuss the budget review the project timeline then finalize the plans.

Explanation: In lists or series that describe processes or sequences, commas (or semicolons for complex lists) before “then” help clarify the order of actions.

Rule 10: Avoiding Commas When Connecting Ideas

Correct Usage:

• She called to say she was leaving and then arrived an hour later.
• He packed his bags and then left without saying goodbye.

Incorrect Usage:

• She called to say she was leaving, and then arrived an hour later.
• He packed his bags, and then left without saying goodbye.

Explanation: When “then” serves to connect closely related ideas or actions without needing a pause for clarity, omit the comma.