Using the word which and commas

Main Takeaways:

• Place a comma beforewhich when which precedes a nonrestrictive clause.
• A nonrestrictive clause is a phrase that adds non-essential information to a sentence without changing the overall meaning.
• Don’t place a commabeforewhich when which is part of a prepositional phrase.
• Don’t use a commabefore which when it’s used to pose an indirect question.
• We use which with nonrestrictive clauses, while we use that with restrictive clauses.
• When used with a restrictive clause, you don’t need to put a commabeforethat.
• Restrictive clauses function as identifiers. Removing a restrictive clause from a sentence changes the sentence’s meaning.

Whether to use a comma before or afterwhich in a sentence is a dilemma that many people face when writing. This grammar guide will teach you when you should and shouldn’t place a comma before which.

When it comes to grammatical conundrums, commas are often the culprit. Thankfully, learning when to use a comma before and afterwhich is actually pretty easy when you follow several simple rules.

When Should You Use a Comma Before Which?

Simply put, you should use a comma beforewhich when it precedes a nonrestrictive modifying clause. A nonrestrictive modifying clause is a phrase that adds nonessential information to a sentence without altering its meaning. It’s normally set off from the rest of a sentence with commas.

In this example, the phrase “which can be difficult to use correctly” is the nonrestrictive modifying clause. It modifies the noun comma, letting us know that commas can be challenging. Without it, however, the primary meaning of the sentence would remain intact.

In the example above, the sentence is correctly punctuated with a comma beforewhich. Another comma, placed after “correctly,” sets the phrase completely apart from the rest of the sentence. This is typical of nonrestrictive clauses.

Note: Nonrestrictive modifying clauses are also known as nonessential clauses or parenthetical expressions.

Should Which Always Be Preceded By a Comma?

The quick answer to this question is no. A comma should always precede which when it introduces a nonrestrictive clause. Otherwise, don’t place a comma prior to which.

There are several other ways that which can be used in a sentence. None of the following ways require a comma before which.

1. When Which Is Used in Prepositional Phrases.

Sometimes which forms part of a prepositional phrase. A prepositional phrase includes a preposition and a noun or pronoun that serves as the object of the preposition. It may also include adjectives that modify the object.

When which appears in prepositional phrases, it’s typically paired with a preposition.

• in which
• on which
• during which
• after which
• from which

When used this way, you don’t need a comma before the which.

2. When Which Forms a Question

Since sentences never begin with commas, it should go without saying that you don’t need one before which when it starts a sentence.

After all, it would look pretty strange if it was written as:

There is, however, another potential scenario when which forms a question. That’s the indirect question. In this scenario, a question is implied rather than asked outright. There is no question mark at the end of the sentence in indirect questions (unless they’re embedded in another question).

Essentially, both examples are asking about what items are on sale. One asks directly, while the other poses the question indirectly.

Comma After Which

Some grammarians believe that a comma can be used after which for reasons of style.

You’ll notice here that by adding a comma after the which, you end up with commas before and after it. This can lead to a choppy sentence. In this case, rephrasing may be the better option.

That vs. Which: Picking the Right Word

When learning how to punctuate a sentence using the word which, it’s important to understand when which isn’t the right word at all.

One Rule to Guide Them All

It’s easy to get tangled up choosing between that and which, but there’s a simple rule for picking the right word. That is used with restrictive clauses. Which is used with nonrestrictive clauses.

Restrictive Clauses

To simplify, restrictive clauses provide essential descriptive information about the noun they modify. They function as identifiers, essentially narrowing things down. They can’t be removed from a sentence without altering the meaning.

The restrictive clause in this sentence, “that are well-trained,” modifies the noun—in this case, dogs. This clause narrows it down to a specific category of dogs: well-trained dogs. You can’t remove the clause without altering the sentence’s essential meaning. That makes it a restrictive clause.

When used this way, there’s no need to place a comma before that.

Nonrestrictive Clauses

As discussed earlier, nonrestrictive clauses add non-essential information to a sentence. Unlike a restrictive clause, a nonrestrictive clause doesn’t alter the main meaning of the sentence.

The nonrestrictive clause, “which Amy got from a rescue,” adds interesting information and context to the noun, dog. However, you can remove the clause from the sentence without changing the meaning.

No Comma Drama

Punctuating sentences can be challenging, and even experienced writers and grammarians often struggle with proper placement of commas. Remembering simple rules of usage can take the drama out of comma placement, letting the meaning of your sentences come through loud and clear.

Quick Comma Before Which Grammar Quiz

Read More: How To Use Commas In Your Writing

Are You Asking a Question?

When you use the word “which” as part of a question, the word could be considered an interrogative pronoun. You’re asking someone to specify one or more items from a definite set. 

Examples:

• Which flavor is your favorite? 
• Which is your favorite?

When you use “which” to ask a simple question, you don’t need a comma. 

You also don’t need a comma before “which” when it’s used as part of an indirect question. An indirect question has been rewritten in a declarative style that doesn’t require a question mark. 

I wondered which is your favorite.

In the case of an indirect question, as in the example above, no comma should be used. On the other hand, when a direct question appears within a longer sentence, it should always be set off by a comma. 

Could you tell me, which is your favorite?

In the example above, the direct question must be set off from the rest of the sentence.

You also need a comma before an interrogative “which” when the word appears in dialogue. That has more to do with the formatting of dialogue than with the word “which”. Even if you replace “which” with another word, you would still need the same formatting for any piece of dialogue. 

She asked, “Which is your favorite?”

He answered, “I don’t know.”

Using “Which” in a Prepositional Phrase

“Which” is frequently used as the object of a prepositional phrase. Keep an eye out for sentences that have a preposition before the word “which,” since that construction indicates that you do not need to use a comma. Common prepositions include: above, across, against, along, among, around, at, before, behind, below, beneath, beside, between, by, down, from, in, into, near, of, off, on, to, toward, under, upon, with, and within. 

• That was the park at which he lost the game. 
• I saw a play in which the main character spoke Japanese. 
• That is a subject of which I am ignorant. 
• The country to which I moved was across the international dateline. 
• The high school from which I graduated was highly ranked. 

When you use “which” after a preposition, you won’t need an additional punctuation mark. 

Using “Which” in a Nonrestrictive Clause

Often, the word “which” appears as part of a clause that isn’t essential to the meaning of the sentence. For instance, the word might appear as part of a parenthetical, explanatory phrase. Parenthetical phrases can easily be removed from the sentence without changing the meaning. They should be identified with a pair of commas. 

Figure skating, which I started at age five, has always been my favorite sport. 

You could easily remove the nonrestrictive clause from the sentence without changing the meaning. 

Figure skating has always been my favorite sport. 

You may also come across the word “which” used in a non-defining relative clause. In this context, “which” introduces a phrase that gives extra information about a person or thing. 

He studied French, which was a subject that he enjoyed.

In the sentence above, the relative clause explains more about the word “French,” but it’s not essential information. Non-essential, nonrestrictive clauses should be set off from the rest of the sentence with a set of commas. If the non-essential clause appears at the end of the sentence, you would only need one comma to set it apart from the rest of the sentence.

Using “Which” in a Restrictive Clause

In other cases, a relative clause may be essential. In those circumstances, we call it a defining relative clause. Often, you can identify a defining relative clause by asking yourself by asking yourself, would I be able to replace “which” with “that”? 

The topic which I enjoy the most is art history. 

The topic that I enjoy the most is art history.

Also, ask yourself whether the phrase is essential. When you remove the phrase “which I enjoy the most,” do you change the meaning of the sentence?

The topic is art history. 

In this case, the meaning changes when you remove the relative phrase. For both of those reasons, we know that “which I enjoy the most” functions as a restrictive phrase in this case, and it therefore does not require commas. 

The example above uses “which” to introduce a defining relative clause. The phrase provides additional information that is essential to the sentence. Interestingly, in American English, people usually prefer the word “that” to “which” in a defining clause or any other restrictive clause. So, when in doubt, you may want to replace “which” with “that” and sidestep the question of whether or not to place commas entirely. Similarly, you could omit the relative pronoun when it’s used in this context. 

The topic I enjoy the most is art history. 

By making these two modifications—either replacing “which” with “that” or omitting the word “which”—you can avoid questions of comma usage. 

Do You Need Commas?

Look at the following sentences and try to determine whether you should use commas. You can find the answer key with proper punctuation below the quiz. 

Quiz

1. Which toy is bouncier?
2. She asked which laundry soap we use. 
3. He asked “Which lamp do you like best?”
4. They prefer the style guide which he advocated.
5. He introduced a comma splice which is a common grammatical error.
6. The Oxford comma which is named after Oxford University Press has long been the subject of arguments. 
7. They want to know which dependent clause should be deleted? 
8. She wanted to buy the ship which won the race.
9. An apostrophe which identifies the possessive case should be used here.
10. Independent clauses which are joined with a semicolon do not need a coordinating conjunction.

Answers

The answers in bold did not need any modifications. 

1. Which toy is bouncier?
2. She asked which laundry soap we use. 
3. He asked, “Which lamp do you like best?”
4. They prefer the style guide which he advocated. Alternative: They prefer the style guide he advocated.
5. He introduced a comma splice, which is a common grammatical error.
6. The Oxford comma, which is named after Oxford University Press, has long been the subject of arguments. 
7. They want to know, which dependent clause should be deleted? 
8. She wanted to buy the ship which won the race. Alternative: She wanted to buy the ship that won the race.
9. An apostrophe, which identifies the possessive case, should be used here.
10. Independent clauses which are joined with a semicolon do not need a coordinating conjunction. Alternative: Independent clauses that are joined with a semicolon do not need a coordinating conjunction.

Sources:

1. https://dictionary.cambridge.org/us/grammar/british-grammar/relative-clauses-defining-and-non-defining
2. http://www.cws.illinois.edu/workshop/writers/restrictiveclauses/
3. https://www.dictionary.com/e/that-vs-which/
4. https://owl.purdue.edu/owl/general_writing/punctuation/commas/extended_rules_for_commas.html
5. https://grammar.collinsdictionary.com/us/easy-learning/interrogative-pronouns

Writing and speaking in American English often includes the relative pronouns which and that. We use these words to provide essential and nonessential (also known as restrictive and nonrestrictive) information that further explains or identifies.

The distinction between which and that was once more established within daily formal writing. The word which was used for nonessential clauses, and the word that was used for essential clauses.

Examples

Here is the stapler, which will be yours until further notice.

Here is the stapler that will be yours until further notice.

In the first sentence, which leads a nonessential clause with information that is clarifying but not vital. Removing the clause would not alter what needs to be communicated. We could write only here is the stapler and our main message would still be intact.

In the second sentence, that leads an essential clause identifying one stapler as distinct from others. The clause thereby “restricts” information, and removing it would alter what needs to be communicated. The recipient would not be aware that the stapler is a specific one that could be taken back later.

Within that once more-fixed usage, punctuation was equally set. A nonrestrictive which clause included a comma or commas; a restrictive that clause did not. However, over time which has gained increasing acceptance as both a restrictive and nonrestrictive pronoun in American English, particularly in informal and mass communication.

Examples

Here is the stapler, which will be yours until further notice.

Here is the stapler which will be yours until further notice.

Here we have which functioning as both an essential and a nonessential marker. This shifts our instrument for understanding the context from the pronoun to the punctuation.

If which is preceded by a comma, it is nonrestrictive. If it is not preceded by a comma, it is restrictive. For those not yet familiar with these precepts, the dual application of which can create hurdles to meaning.

The following guidelines will help you maintain clarity in your writing by knowing when to use a nonrestrictive which clause with an identifying comma before it.

Comma Before Which: Nonrestrictive Clauses

Although popular style may use which both restrictively and nonrestrictively, we as precise writers will aim to maintain the distinction by applying which as a nonrestrictive relative pronoun.

Use one comma before which when the nonessential clause ends a sentence:

Jermaine has the toolbox, which is mine.

When the nonessential clause appears in the midst of a sentence, use a comma before and after the which clause.

Jermaine has the toolbox, which is mine, and he will return it later today.

Comma Before Which: Prepositional Phrases

The word which is often paired with prepositions. Just a few examples include:

We would not use a comma before or after which when it is part of a prepositional phrase.

Correct: That is the location at which we’ll arrive by 7 p.m.
Incorrect: That is the location at, which we’ll arrive by 7 p.m.

Correct: To which address should he send this?
Incorrect: To, which address should he send this?

Correct: That is the basis upon which the jury will judge the outcome.
Incorrect: That is the basis upon, which the jury will judge the outcome.
Incorrect: That is the basis upon which, the jury will judge the outcome.

Comma Before Which: Indirect Questions

The word which commonly opens a direct question (also referred to as an interrogative sentence):

Which way is the bank?

Which dress are you wearing to the dance?

Which bat will Babe use during the game?

The same questions might also be indirect ones presented as declarative statements. We would not use a comma before which when it is part of an indirect question.

Examples

I asked him which way the bank is.

Brynne wants to know which dress you are wearing to the dance.

The fans are curious which bat Babe will use during the game.

When the question beginning with which is part of dialogue with preceding attribution, we would include a comma before it:

I asked, “Which way is the bank?”

Related Topics

That vs. Which
Restrictive Clause: What Is a Restrictive Clause?
Nonrestrictive Clause: What Is a Nonrestrictive Clause?

Pop Quiz

Insert commas wherever they belong with the word which in the following sentences. If a use of which does not require a comma or commas, leave it be.

1. Jessica asked Marlon about the heirloom which has been in his family for centuries.

2. The answer to the question which we’ll have tomorrow may surprise all of us.

3. Fatmir asked “Which fact will sway Maribella?”

4. On which day will they hold the auction?

5. Which stain on the rug are you talking about?

Pop Quiz Answers

1. Jessica asked Marlon about the heirloom, which has been in his family for centuries.

2. The answer to the question, which we’ll have tomorrow, may surprise all of us.

3. Fatmir asked, “Which fact will sway Maribella?”

4. On which day will they hold the auction? No commas

5. Which stain on the rug are you talking about? No commas

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