It can be tricky to work out when the word “but” needs a comma before or after it. Even professional copywriters get this wrong sometimes. But it doesn’t have to be difficult. Once you’ve learned a few simple rules, this grammatical stumbling block becomes much easier to understand.
- You only need a comma before "but" sometimes
- A comma goes before "but" when "but" is connecting two independent clauses
- Correct use: I want to buy a new car, but I don't have any money
- Incorrect use: I would buy a new, but for the cost.
Let's take a closer look so that you'll never wonder whether to use a comma before "but" again.
When Do You Need a Comma Before But?
Short answer: sometimes, but not always. The way to work this out is to look at the two parts of the sentence this punctuation mark is separating. The basic rule is this: you should put a comma before “but” only when it is connecting two independent clauses.
Independent clauses are parts of a sentence that could function as complete sentences of their own. They have a subject and an object.
I want to buy a new car, but I don’t have any money.
In this sentence, each clause on either side of “but”—“I want to buy a new car” and “I don’t have any money”—could work as two complete sentences. This shows they are independent clauses, and it's correct to use a comma before but.
Dependent clauses are the opposite of independent clauses—they would not work as standalone sentences.
I would buy a new car but for the cost.
In this variation on the previous example, the clause after but is “for the cost”. This would not make sense on its own as a sentence. It requires the first part of the sentence to provide context.
Therefore, when the word “but” connects an independent clause to a dependent clause, you should not use a comma.
Some More Examples
Here are some more sentences which correctly use—or don’t use—commas before “but.”
Think about whether the clauses are independent or dependent, and how this has informed the comma usage.
- The bakery is far away but sells amazing cookies.
- The bakery is far away, but it sells amazing cookies.
- Julia went to the post office, but she forgot to take her shopping list.
- Julia went to the post office but forgot her shopping list.
- Learning punctuation rules is a tedious experience, but it improves your writing.
- Learning punctuation rules is a tedious but worthwhile experience.
It’s worth noting that this same rule applies to all other coordinating conjunctions; For And Nor But Or Yet So. All you need to do is remember the handy acronym FANBOYS.
Do You Need a Comma After But?
Most of the time, you don’t need a comma after “but”—including when you start a sentence with it. For example:
But it doesn’t have to be so difficult.
There is no need for a comma here. However, there is an exception to this…
Comma Usage With Interrupters
The only times where you do need the comma after “but” are when it is immediately followed by an extra word or phrase.
Here is an example:
But, of course, it doesn’t have to be so difficult.
Here, “of course” is what’s known as an interrupter—an extra subordinate clause that interrupts the flow of the main clause and so needs to be separated off using a pair of commas.
The same rule applies when “but” does not begin the sentence:
Learning grammar is important, but, of course, it doesn’t have to be difficult.
In other cases, the interrupting clause works like an adverb to add additional meaning to the main clause that follows it. It’s often known as an introductory phrase or introductory word.
Here are some more examples of these:
But, from the beginning, he was the best member of the team.
But, naturally, I forgot all the grammar rules after learning them.
3 quick tips for remembering if you need a comma before or after but
To summarize, if you’re unsure is a sentence with "but" needs a comma or not, answer these three sentences:
- Does the word “but” link two phrases that would work as sentences on their own?
If yes, put a comma before “but.”
- Does “but” link one phrase which would work as a standalone sentence with one that does not?
If yes, you do not need a comma beforehand.
- Is the word “but” followed by an interrupter word or phrase?
If yes, put a comma after “but.” If no, you do not need a comma after it.
An easy way to check whether your sentence fits the first or second criteria on this list is to break it into pieces—the piece before and after “but.” Test each piece on its own. Does each one have a subject (noun or pronoun) that performs an action (verb)?
Use this test and the tips above consistently in your writing, and soon the correct way to punctuate before and after the word “but” will become intuitive to you. Then you'll never have to worry about getting it wrong again.
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