Using a Comma Before (and After?) “But”

Do you struggle with deciding whether to use a comma every time you write but in a sentence? Well, let’s end the hesitation once and for all:

When Should You Put a Comma Before But?

This issue can be addressed with a simple rule: a comma should be used before but only when the preposition is linking two independent clauses. For example:

RIGHT: I would go for a stroll, but the weather is terrible.

To check for independent clauses, follow these two steps:

  1. Check the phrase that precedes butI would go for a stroll.
  2. Now see the phrase that follows butthe weather is terrible.

As you can see, both phrases make sense on their own, and can stand along as complete sentences. In this scenario, we have two independent clauses, therefore you must use a comma before but.  

When you don’t have independent clauses, leave the comma out.

WRONG: I would go for a stroll, but for the rain.

In this case, the conjunction is linking an independent clause to a dependent clause. You can tell tell this by looking at what is written after butfor the rain.

That phrase has no meaning on its own and can not stand as a complete sentence. Therefore it is a dependent clause. In this case, no comma is needed before the conjunction:

RIGHT: I would go for a stroll but for the rain.

Here are a few more examples

WRONG: The dog is only a puppy, but well trained.

RIGHT: The dog is only a puppy but well trained.

WRONG: Grammar is tedious, but necessary.

RIGHT: Grammar is tedious but necessary.

WRONG: The dog is only a puppy but he’s well trained.

RIGHT: The dog is only a puppy, but he’s well trained.

RIGHT: The car is old but fast 

WRONG: The car is old, but fast

The comma rule applies to the other conjunctions as well: andor, and so.

When Do You Put a Comma After But?

If you are wondering whether a comma is need after the word but, chances are it is not.

You should only use a comma after but when the preposition is immediately followed by an interrupter, i.e., a short word or phrase that interrupts a sentence to express emotion, tone, or emphasis.

REMEMBER: when there is an interrupter in the sentence, it must be preceded and followed by a comma. For example:

But, of course, it’s not prudent for Charlie to go outside on his own.

In the example above, of course is an interrupter. Even if you remove it, the entire sentence will not lose its meaning. The only reason it is added is to reinforce the statement.

If your sentence includes an interrupter directly after but, then you can use a comma. In all other cases, you will not need a comma after but.

Now learn about serial commas in another article titled “Serial Commas: Your Side, My Side and Their Side.”





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