Rule 1: Use a comma before “but” when you use “not only…but also” to connect two clauses, and the second clause is independent.
- Correct: Not only does she work as a teacher, but she also volunteers to help orphans.
- Incorrect: Not only does she work as a teacher but she also volunteers to help orphans.
Rule 2: Do not use a comma with “not only…but also” when you use it to connect nouns.
- Correct: My favorite day is not only Saturday but also Sunday.
- Incorrect: My favorite day is not only Saturday but also Sunday.
Keep reading the rest of the article to learn more about the comma rules for the term “not only…but also.”
When to Use a Comma With “Not Only…But Also”
When you need to decide about comma placement with the term “not only…but also,” you should refer to Rule 1.
Rule 1: Use a comma with “not only…but also” when you use it to join two clauses.
When you do this, the second clause must be independent. I.e., it must make sense by itself, without the first clause.
When you use “not only…but also” to connect clauses, the first half will be in the first clause, and the second half will be in the second.
- Not only did she study advertising, but she also owns her own marketing company.
- He not only embarrassed himself, but he also offended everyone there.
Furthermore, the Chicago Manual of Style reinforces the rule mentioned above. However, they also state that you do not need to put a comma when the second clause is dependent or contains no subject.
- Not only did we go to the supermarket but also the furniture store.
- Not only do they own a house in the city but also a country vacation home.
When to Avoid a Comma With “Not Only…But Also”
If you want to learn when you should avoid using a comma with “not only…but also”, you should refer to Rule 2.
Rule 2: You shouldn’t use a comma with “not only…but also” when you use it to connect nouns.
When you do this, the nouns will usually be in the same clause, so you do not need to put a comma.
- She has not only a car but also an off-road vehicle.
- He works not only as an accountant but also as a financial advisor.
Conclusion
When you use “not only…but also” to connect clauses, you should always put a comma. E.g., “Not only does she own a house in NY, but she also has a place in Florida.” Alternatively, do not use a comma when you are connecting nouns. E.g., “He eats not only fish but also shellfish.”