When to use a comma before or after but takes a little practice. But once you know the easy punctuation rules, you will have no problem at all.
It can be a little confusing at first. But the comma rules to help you decide are super easy to learn, use, and remember.
Let’s look at when a comma is required or not with the word but.
Once you understand the rules you can always make the correct decision.
Is there a comma before but?
Yes, there is often a comma. However, it depends on two simple and easy to remember grammar rules.
Once you understand these two rules, it will be easy to decide.
All you need to do is look carefully at your complete sentence.
Two simple but comma rules
There are two basic and simple rules to follow for the use of a comma before but.
1. You insert a comma before but when the two halves of your sentence can stand alone.
2. You omit the comma before but when the two sentence halves can’t stand alone.
When do you use a comma before but?
All you need to do to make sure you are correct is to check if your sentence is joining two independent clauses.
In this case, both clauses will have a subject and a verb.
If each part of your sentence is independent, they can stand alone as whole sentences.
Then but, which is your coordinating conjunction, needs a comma to separate your two clauses.
Here are some examples for you.
I wanted to go out for breakfast but my local cafe was closed. Incorrect
I wanted to go out for breakfast, but my local cafe was closed. Correct
This is because each part of the sentence can stand alone as individual complete sentences.
Each one has a subject and a verb. Therefore you are connecting two independent clauses.
I wanted to go out for breakfast. Complete My local cafe was closed. Complete
He left home early, but he forgot to take an umbrella. Correct
My sister is leaving for Canada tomorrow, but she will be back in three weeks. Correct
Susan doesn’t like sardines, but her sister loves all kinds of fish. Correct
We really wanted to go to Spain for our holiday, but the hotels are too expensive in summer. Correct
I meant to buy some bread, but I forgot to stop off at the bakery. Correct
When do you omit the comma before but?
When the second part of a sentence is a dependent clause, there is no comma before but.
It happens when you cannot make a logical sentence from the second clause. It is because it is dependent on the first clause for its meaning.
Usually, this is because there is no subject with a verb in the second clause.
Look at these examples.
The restaurant was fantastic, but very expensive. Incorrect
The restaurant was fantastic but very expensive. Correct
It is because the second word or phrase is not a complete sentence.
The restaurant was fantastic. Complete Very expensive. Incomplete
Studying grammar is hard sometimes but interesting all the same. Correct
I went to the concert but left early with a headache. Correct
The rest of the sentence was easy to write but with no comma. Correct
Going to the gym is tough some mornings but good fun all the same. Correct
He played as well as he could but lost the match. Correct
You can see from the sentences above that there is no subject with a connecting verb in the second clause.
Be careful, though, because there can be a verb. But if it doesn’t have a subject, it is not an independent clause.
You can see this is the last example sentence above with the verb lost.
Can you use a comma after but?
If you start a sentence with but, you usually don’t need to use a comma.
You might want first to refresh your memory about starting a sentence with but.
But only needs a comma after it when there is an adverbial clause or an extra phrase inserted following it.
Think of a comma after but at beginning of a sentence as marking an interruption to a sentence.
But, yes indeed, there is plenty of space in the car for you.
But, on the other hand, I might go to Spain instead.
I was going to buy tickets for the new show, but, in fact, my husband had already bought them for me.
But, if you really want to know the truth, I can’t stand my boss.
It’s not easy, but, well, you know how it is.
The good news about the but comma
Does the comma go before or after but? Now you know the answer.
You have mastered the comma rule with but. I told you it was super easy.
Now I have some even better news for you.
You can use the same three-part rule for a sentence with commas for and, or, yet and so as well.
1. Use a comma before the conjunction when the two sentence halves can stand alone.
2. Don’t use a comma before the conjunction when the second clause can’t stand alone.
3. Use a comma after the conjunction when it is followed by an interruption.
Examples of the comma before and, so, yet and or
He went to London for two weeks, and he stayed at an expensive hotel.
Susan loves her cat, and she lets it sleep in her bed.
Mary loves her dog, yet she doesn’t let it onto in her bed.
There was no chance of changing our flight, so we had to stay for two more days.
Tim missed his train, so he was two hours late for the meeting.
You can try for a free upgrade, or you can pay extra to be sure you get it.
Don’t pack too much, or you will be charged for excess baggage.
Examples of the comma after and, so, yet and or
He went to London for two weeks, and, just like him, he stayed at an expensive hotel.
Susan loves her cat, and, naturally, she lets it sleep in her bed.
Mary loves her dog, yet, like many dog owners, she doesn’t let it onto in her bed.
There was no chance of changing our flight, so, unfortunately, we had to stay for two more days.
It is very easy to learn the comma punctuation rules for coordinating conjunctions.
You can also use a reliable grammar checker to help you check for your correct comma usage.
All you need to do is take a few minutes to make sure you understand the basic rules and then lock them away in your memory.
If there is a subject with a verb in the second clause, use a comma. If there is no subject with a connecting verb, omit the comma.
Here is a screenshot of some of my article text in Prowritingaid. You can see that the mistake is clearly marked with an explanation of the comma problem with but.
You can always do a similar check if you are a Grammarly user.
And yes, I just did a full check, and I got all green lights for my comma usage.
Yes, there are a few complicated comma rules. The ones for cumulative and coordinate adjectives can be a bit tricky.
But for but, it is easy to get it right every time.
I am always reminded of this quote when I think about using commas.
“I spent all morning putting in a comma and all afternoon taking it out.” – Oscar Wilde
It is true that comma usage is complex and often open to interpretation. It is especially so for the Oxford Comma.
But, luckily, it is easy with and, but, yet and so. So you can leave all the other comma rules for another day.