When to Use a Comma Before or After ‘But’: Rules for Punctuation Precision

Comma Before “But” — See the Pattern

Look at these sentences. Some have a comma before “but” and some do not. Can you see why?

She was hungry, but there was no food at home. (two full sentences)

He is tired but happy. (two words — no comma)

I wanted to go outside, but it started raining. (two full sentences)

The room was small but clean. (two words — no comma)

Did you see the pattern? When each side of “but” is a full sentence (with its own subject and verb), you add a comma. When “but” just connects two short words, you leave the comma out.

When to Use a Comma Before “But” and When Not To

Rule 1: Two full sentences → comma before “but”

If both sides of “but” could be their own sentence, put a comma before “but.”

• She wanted the job, but she did not get it.
• He ran fast, but he still missed the bus.

Rule 2: Two words or short phrases → no comma

If “but” only connects two small words or phrases (not two full sentences), skip the comma.

• She is young but smart.
• He tried hard but failed.

Rule 3: Comma after “but” — only with an extra phrase

You almost never put a comma after “but.” The only time you do is when a small extra phrase comes right after “but.” This extra phrase could be removed and the sentence would still make sense.

• He wanted to leave, but, to be honest, he was too tired to move.
• She agreed, but, surprisingly, she changed her mind the next day.

If there is no extra phrase after “but,” do not put a comma after it.

Easy way to remember: Cover the word “but.” Can each part be its own sentence? If yes → comma before “but.” If no → no comma.

Real-Life Examples With Commas and “But”

Here are sentences you might say or write in everyday life:

I wanted to sleep in, but my alarm went off at six. (two full sentences — “I wanted to sleep in” and “my alarm went off at six” can each stand alone)

The food was cheap but delicious. (two words describing the food — no comma needed)

She studied all night, but she still felt nervous before the exam. (two full sentences)

He is quiet but kind. (two words describing him — no comma needed)

We waited for an hour, but the doctor never came. (two full sentences)

You are doing great. Now let us look at the mistakes many learners make.

Three Mistakes to Avoid With Commas and “But”

Even native English speakers get confused about commas with “but” — so if this feels tricky, you are not alone. Here are the most common mistakes and how to fix them.

Mistake 1: Adding a comma when “but” joins two words

Mistake 2: Forgetting the comma when “but” joins two full sentences

Mistake 3: Putting a comma after “but” when there is no extra phrase

How to remember: The comma test is simple. Cover the word “but” and read each part by itself. If both parts make sense as full sentences on their own, you need a comma before “but.” You almost never need a comma after it.

Test Yourself: Comma or No Comma With “But”?

Choose the correct answer for each sentence. Click Check to see if you are right.

Keep Going — You Are Building Something

You just learned when to use a comma before “but.” That is one more punctuation rule you will never get wrong again.

But here is something interesting. Have you ever seen a sentence like this: “I like pizza, I like burgers”? That looks fine, right? Actually, it is a very common writing mistake called a comma splice. It happens when you use a comma to join two sentences without a word like “but” or “and.” Do you know how to fix it?

Next lesson: What Is a Comma Splice and How to Fix It