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EM
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Articles
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Punctuation
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Pronouns
Summary
No comma is needed before or after the word that, whether used as a relative pronoun or a conjunction.
Examples
- Incorrect: The parcel, that came this morning contained seeds.
Correct: The parcel that came this morning contained seeds. - Incorrect: Today I learned that, islands are mountains in the sea.
Correct: Today I learned that islands are mountains in the sea.
Use a comma before which when it introduces a nonrestrictive clause (one that provides extra, optional information). Remember to use a comma both before and after the which clause.
Example
- Incorrect: This shirt which I ordered online is the wrong size.
Correct: This shirt, which I ordered online, is the wrong size.
Which can replace that to introduce a restrictive clause, providing information essential to meaning. Commas are then omitted. (Such use is seen more often in British than American usage.)
Example
- Incorrect: Oceanic islands are islands, which do not sit on continental shelves.
Correct: Oceanic islands are islands which do not sit on continental shelves.
Finally, no comma is needed before or after which when it is used after a preposition or in an indirect question.
Examples
- This is a story in which nothing happens.
- They asked which flight we had booked.
That and which
The words that and which are relative pronouns that help describe nouns. Commas are used depending on whether the description is essential to meaning or whether it merely provides additional, optional information.
Examples
- Cats that like cheese love pizza.
- I have a shirt that might fit you.
- Such medicines, which relieve acidity, are called antacids.
- Anita got a job in Paris, which is what she wanted.
That and which also have other uses. That can be used as a conjunction to introduce a subordinate clause. Which appears in prepositional phrases (in which, on which) and indirect questions.
Examples
- Anita said that she wanted to go to Paris.
- The house in which she lived was built in 1913.
- Ask Tumkin which pizza he wants.
In this article, we discuss when to use commas with that and which.
Comma with that
No comma is needed before or after the word that. As a relative pronoun, that introduces a restrictive clause, which contains a description necessary to identify the person or thing being referred to. Since such information is essential to meaning, it is not enclosed in commas.
Examples
- Incorrect: Cars, that run on solar power, are better for the environment.
“Cars are better for the environment” doesn’t convey complete meaning. Which cars? The ones
that run on solar power
. That introduces a clause essential to meaning; don’t enclose it in commas.
Correct: Cars that run on solar power are better for the environment.
- Incorrect: Here is a list of fruits that, last forever in the fridge.
Correct: Here is a list of fruits that last forever in the fridge. - Incorrect: Elephants are mammals, that can’t jump.
Correct: Elephants are mammals that can’t jump. - Incorrect: Your website should have a URL, that’s memorable.
Correct: Your website should have a URL that’s memorable.
Tip
Don’t use commas around any description essential to meaning (whether or not you use the word that).
Example
- Incorrect: The phone, I bought online is broken.
Which phone? The one
I bought online
.
Correct: The phone I bought online is broken.
The word that is also used as a conjunction to introduce a subordinate clause. Again, no comma is needed before or after that.
Examples
- Farley thought that dragonflies were baby dragons.
- Lulu said that she wanted more cake.
- I’m glad that you called.
A comma may be used after that if it is followed by an interrupter or other parenthetical phrase.
Examples
- Anita said that, all things considered, she prefers tea to coffee.
- We wanted a car that, in the long run, would do less harm to the environment.
- It was a parcel that, surprisingly, contained seeds.
Comma with which
Use a comma before which when it introduces a nonrestrictive clause (an additional, optional description) in a sentence. Such information may be interesting and even useful but is not essential to meaning. It is therefore enclosed in commas.
Examples
- Incorrect: Farley’s new phone which he bought just yesterday has already stopped working.
Even without the which clause, we know which phone is being referred to:
Farley’s new phone
. Enclose the extra information in commas.
Correct: Farley’s new phone, which he bought just yesterday, has already stopped working.
- Incorrect: She comes from Pouthena which is the capital of Nusquam.
Correct: She comes from Pouthena, which is the capital of Nusquam. - Incorrect: This recipe calls for seven eggs which makes no sense at all.
Correct: This recipe calls for seven eggs, which makes no sense at all.
Caution
Remember to use a comma not just before but also after the which clause.
Example
- Incorrect: This phone, which I bought ten years ago still works fine.
Correct: This phone, which I bought ten years ago, still works fine.
The relative pronoun which can also replace that to introduce defining or restrictive clauses (which provide information essential to meaning). Commas are then omitted.
Examples
- The flowers which came this morning are for you.
- The house which Farley built has fallen down.
- One of the marbles which were here is missing.
Note
In formal British usage, which is preferred over that in restrictive clauses (information essential to identify the person or thing being referred to). In contrast, in edited American prose, that is preferred over which.
Example
- Formal (British): Penguins are birds which cannot fly.
Formal (American): Penguins are birds that cannot fly.
Don’t use a comma before which when it acts as the complement of a preposition (in which, of which).
Examples
- Incorrect: The parcel in, which the seeds arrived had no label.
Correct: The parcel in which the seeds arrived had no label. - Incorrect: The book on, which this movie is based was written by a friend of mine.
Correct: The book on which this movie is based was written by a friend of mine.
Also don’t use a comma before which in indirect and reported questions.
Examples
- Incorrect: Lulu asked me, which book I wanted.
Correct: Lulu asked me which book I wanted. - Incorrect: I wonder if you know, which bus I should take.
Correct: I wonder if you know which bus I should take.
Examples from literature
The following examples show how that is used to introduce an essential clause. No commas are necessary or used.
Examples
I’ve never come across a definition that satisfied me, though there are some very good ones.
I was young and not gloomy and there were always strange and comic things that happened in the worst time.
In these sentences, that is used as a conjunction to introduce a subordinate clause. Again, no commas are needed.
Examples
And I knew that it was better to live out one’s absurdity than to die for that of others.
In university they don’t tell you that the greater part of the law is learning to tolerate fools.
Note how a comma is used before which when it introduces an optional, nonessential description.
Example
Pink is supposed to weaken your enemies, make them go soft on you, which must be why it’s used for baby girls.
Finally, when which is used in place of that to introduce a restrictive clause (one that provides information essential to meaning), no commas are used.
Example
But there was happiness elsewhere which no description can reach.
Usage guide
Don’t use a comma before or after the word that, either as a relative pronoun (when it introduces information essential to meaning) or as a conjunction (when it introduces a relative clause). The word which is also used as a relative pronoun, but it generally presents an optional description, which you should enclose in commas (remember to use commas both before and after the which clause). In British usage, which often replaces that to present information needed to identify the person or thing being referred to; commas are then omitted. When which is used with a preposition (of which, in which), no comma is needed before or after the word. Finally, don’t use a comma with which when it appears in an indirect or reported question.
Examples
- Correct: That as relative pronoun: Tree kangaroos are marsupials that live in trees.
- Correct: That as conjunction: You thought that tree kangaroos weren’t real.
- Correct: Which as relative pronoun (nonrestrictive): Tree kangaroos, which look like a cross between a kangaroo and a lemur, are found in Australia, Indonesia, and Papua New Guinea.
- Correct: Which as relative pronoun (restrictive): They are marsupials which have evolved to live in trees.
- Correct: Which as complement of preposition: Here is a list of countries in which tree kangaroos are found.
- Correct: Which in indirect question: She wanted to know which animal I was talking about.
1) Do not place a comma before «that»; 2) Do not place a comma before who or which if the information provided by the relative clause is essential; 3) Place a comma before who or which if the relative clause is not necessary to know who or what the speaker means.
When using the relative pronoun «who«, «which«, or «that» in a sentence:
- Do not place a comma before «that«:
The man that lives next door is tall.
The man, that lives next door, is tall.
-
Do not place a comma before «who» or «which» if the information provided by the relative clause is essential to understand which person or thing the writer is talking about.
The man who lives next door is tall.
The man, who lives next door, is tall.
We need the relative clause «who lives next door» to know exactly who is the man the writer is talking about. We do not use commas in a situation like this.
-
Place a comma before «who» or «which» only if the relative clause is not necessary to know who or what you are talking about. That is, the relative clause provides additional information about the person or thing, but this extra information is not essential to identify the subject.
My neighbor Peter, who lives next door, is very tall.
Even if you omit the clause «who lives next door», the reader knows who you are talking about (your neighbor Peter). The clause «who lives next door» just adds extra information.
When someone or something is sufficiently identified, the description that follows is considered nonessential and should be surrounded by commas.
Contents
- 1. Using Commas with Relative Pronouns
- 2. Using a Comma Before ‘Who’ or ‘Which’ Changes the Meaning of a Sentence
- 3. When to Use ‘That’, ‘Who’ and ‘Which’
- 4. More Examples
1. Using Commas with Relative Pronouns
Look at this example:
People who live in cities are more stressed.
«Who live in cities» is a relative clause (a part of the sentence that tell us what type of person or thing the speaker means). Relative clauses begin with relative pronouns, such as «who«, «which«, or «that«.
The children who read at home regularly make the most progress.
The clause «who read at home regularly» is essential to understand the meaning of the sentence. If we omit this clause, the sentence makes no sense.
The children make the most progress.
The sentence above is incorrect since we are trying to say that only some students, those who read at home regularly, make the most progress.
Another example:
My brother, who works as a dentist, is wealthy.
If we take out the relative clause («who works as a dentist»), the sentence is complete and makes sense. It also provides the most relevant information (My brother is wealthy.)
When using a comma before «who» or «which», include also the closing comma (the comma after «dentist» in the example above). Some writers forget to add this important comma. At the end of a sentence, a period replaces a comma.
2. Using a Comma Before ‘Who’ or ‘Which’ Changes the Meaning of a Sentence
Examine this example:
My sister, who is very tall, can speak English and French.
This sentence is correct because you are assuming that the reader knows who you are talking about (your sister).
However, if you have two sisters, the reader may need to know which sister you are speaking about. Remember, we should avoid commas if the information is essential to know who or what you are talking about:
My sister who is very tall can speak English and French.
Another example:
I’m planning to go to Spain which is very sunny next month.
In this sentence, the comma is not optional. The clause before the relative pronoun tells us where you are going (Spain). In this particular context, the relative clause «which is very sunny» just adds extra information about Spain.
I’m planning to go to Spain, which is very sunny, next month.
- We use «who» for people (sometimes for animals too).
She doesn’t like people who get angry easily.
I don’t like movies who have scenes of violence.
- We use «which» for things.
I only buy watches which are waterproof.
My uncle, which is an engineer, went to London last week.
- We use «that» for people or things.
The girl that came last week is smart.
The dish that you prepared yesterday was delicious.
- «That» is more common than «which«, but sometimes you need to use «which» (see next point).
Rebecca works for a company that makes drones.
I don’t like movies that have scenes of violence.
- If the sentence requires commas, you should use «which» for things and «who» for people (not «that»).
Madrid, which is the capital of Spain, was founded around the year 860 A.C.
Alex, who is very tall, is a good chess player.
- In many situations, you can omit the pronoun in a relative clause. You can learn more about how to omit correctly that, who, or which.
Remember, we don’t put a comma before that.
Paris, that is the most romantic city in the world, is a beautiful place to live.
Paris, which is the most romantic city in the world, is a beautiful place to live.
Another example:
Rebecca, that lives in New York, is very smart.
Rebecca, who lives in New York, is very smart.
4. More Examples
Examples with «who«:
- The waiter who served us was rude.
- What was the name of the person who came yesterday?
- The man who was carrying a suitcase was very polite.
- My friend Olivia, who lives next door, is an engineer.
- What was the name of the person who wanted to talk to you?
- The police caught the girl who stole the wallet.
- Marie Curie, who was the first woman to win a Nobel Prize, discovered the existence of the elements polonium and radium.
- The movie was about a boy who was raised in Paris.
- A firefighter is a person who fights fires and rescues people.
- Do you know who took those pictures?
Examples with «that«:
- The restaurant that was destroyed in the fire has now been rebuilt.
- The protester that was arrested has hired a new lawyer.
- What happened to the hamburger that was on the table?
- A paradox is a statement or proposition that is seemingly contradictory.
- Andorra is a microstate that borders France and Spain.
- Thailand is the only Asian country that was never colonized by a European country.
- The company that was fined for air pollution is now investing in renewable energy.
Examples with «which«:
- Artificial intelligence, which combines computer science and robust datasets, enables the execution of complex tasks.
- The new stadium, which can hold 20,000 people, has an oval shape.
- We often go to Chicago, which is not far away.
- Inflation, which is pretty high right now, is having an impact on US consumers.
- Yoga, which improves core strength and flexibility, is very popular in India.
Commas are one of the most common punctuation marks in English, but they’re also one of the trickiest to use.
There are so many rules around comma usage, and they vary according to different circumstances.
For example, is it grammatically correct to use a comma before that?
You need a comma before that when the word is introducing parenthetical information anywhere in a sentence, plus a few other instances.
In this article, we’ll show you when to use commas before that, along with examples to help you get it right every time.
Is There a Comma Before That or After That?
You should use a comma before that when it introduces a parenthetical phrase. You should use a comma after that when it closes a parenthetical phrase.
A parenthetical element adds additional information and color to a sentence, but isn’t essential to the overall meaning.
For example:
- Georgina, that girl sitting in the red chair, is actually my former roommate.
In the example above, “that girl sitting in the red chair” provides extra information, or what’s referred to as non-essential or non-restrictive information. If you remove it from the sentence, the meaning remains the same.
Parenthetical phrases always need enclosing with punctuation marks. These can include commas, curved brackets, square brackets, or dashes. These punctuation markers are a useful way to identify non-restrictive information.
When to Use a Comma Before That
A comma before that is necessary when it introduces a parenthetical phrase in the middle or at the end of a sentence. For example:
- I won’t make that mistake again, that’s for sure.
- He doesn’t want to go to university, that much is obvious, he just wants to please his parents.
In these contexts, the comma acts as a parenthetical comma that offsets the parenthetical expression.
Another way to use a comma before that is when writing the parenthetical phrase that is. This is a shortened version of that is to say.
For example:
- The South American countries, that is, Brazil, Colombia, and Argentina, were doing very well economically.
Here, the clause that is is an introductory parenthetical phrase within a larger parenthetical element—one that begins with that and ends with Argentina.
It’s also grammatically correct to include a comma before that when it’s used in the middle of a list. Normally, a comma would not precede the first term in a list.
- Which dress is your favorite? This one, that one, or the other one?
When to Use a Comma After That
A comma after that is necessary if it occurs at the end of a parenthetical element in the middle of a sentence. This is because the comma is acting as a closing parenthetical comma.
- He threw a bar stool across the room, though I didn’t witness that, and was thrown out of the party.
If the parenthetical phrase occurred at the end of the sentence, there would be a period after that, rather than a comma.
You should also use a comma after that when it’s a term at the start or in the middle of a list. In the example below, the comma is acting as an Oxford comma, rather than a parenthetical comma.
- I’m not sure Hannah’s free today. She’s doing this, that, and the other.
No Comma Before That or After That
So when shouldn’t you use a comma before or after that? When there’s no need for a parenthetical comma, or when that is not part of a list.
This means you shouldn’t use a comma when that is functioning as an adjective, pronoun, determiner, adverb, or conjunction.
In particular, you shouldn’t use a comma before or after that when it’s used to join the main clause with a restrictive relative clause.
A relative clause is a type of subordinate clause that starts with a relative pronoun, such as that, who, when, which, or where. Relative clauses can be restrictive or nonrestrictive. A restrictive clause contains essential information.
For example:
Incorrect: Your mom mentioned, that you were upset.
Incorrect: Your mom mentioned that, you were upset.
Correct: Your mom mentioned that you were upset.
In the example above, “that you were upset” is a restrictive clause because it contains the essential details. Without it, the sentence loses its meaning. You shouldn’t use a comma to set apart a restrictive clause.
Parenthetical elements are nonrestrictive clauses because they contain information that isn’t essential to the meaning of the sentence. That’s why we use commas or another type of parentheses to set these phrases apart.
Commas aren’t used before or after that in an indirect statement either. An indirect statement is a form of subordinate clause. It’s used for reporting what someone said or wrote without using their exact words.
Notice how a comma is not appropriate before or after that in this example:
- Jerry said that he was going to buy a new car.
Examples of That in Sentences
Let’s look at a few grammatically correct examples of how to use a comma before that.
- He didn’t want to lose her friendship, that would be agonizing, but it was his only option.
- Julia, that girl over there, is actually my former roommate.
- My new coat, that one with the navy stripes, is missing a button already.
- Eric, that’s his wife over there, is the new chairman.
- Jake, that is, my younger brother, is going to summer camp next month.
Final Thoughts on Comma Before That
Let’s summarize what we’ve learned about the correct way to use a comma before that.
If that introduces a parenthetical expression, then it must be preceded by a comma. You should use a comma before that if it appears in the middle of a list too.
Other than these two instances, there’s no need for a comma before that if it’s carrying out its other functions—as an adverb, pronoun, determiner, conjunction, or adjective.
If you’re concerned about making grammatical mistakes in your work, ProWritingAid will pick up any instances of missing or misused commas.
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Tip: See my list of the 
Most Common Mistakes in English. It will teach you how to avoid mistakes with commas, prepositions, irregular verbs, and much more.
What distinguishes English from most other languages is its use of commas before a dependent (subordinate) clause. Dependent clauses (clauses introduced by words like “that”, “which”, “who”, “where”, “how”, etc.) are usually neither preceded nor followed by a comma. For example:
correct Cars that don’t have seat belts aren’t allowed to carry children.
wrong Cars, that don’t have seat belts, aren’t allowed to carry children.
correct I don’t know which one I want.
wrong I don’t know, which one I want.
correct Could you tell me where it is?
wrong Could you tell me, where it is?
Dependent clauses are (and in fact must be) separated with commas only when the information contained in the clause is not important for the overall meaning of the whole sentence. A good way to recognize such clauses is to try to enclose the clause in parentheses; if the sentence still makes sense, you should use commas (or parentheses) to separate the clause from the rest, e.g.
Brazil nuts, which you can buy in a supermarket,
are a great source of selenium.
Commas were appropriate here because we could replace them with parentheses:
Brazil nuts (which you can buy in a supermarket) are a great source of selenium.
Not using commas or parentheses would be a mistake in this case. The sentence
Brazil nuts which you can buy in a supermarket are a great source of selenium.
implies that only Brazil nuts sold in a supermarket (and not elsewhere) are a great source of selenium, which is certainly not the case.
Notice how the three examples we used at the beginning wouldn’t make sense if we put the dependent clause in parentheses:
wrong Cars (that don’t have seat belts) aren’t allowed to carry children.
wrong I don’t know (which one I want).
wrong Could you tell me (where it is)?
Going back to the title of this article—“that” can be used only in clauses containing essential information; it is not correct to write:
Brazil nuts (that you can buy in a supermarket) are a great source of selenium.
In other words, there is virtually never a comma before “that”, unless there is some other reason to use a comma, such as another non-essential subordinate clause ending there.
There is also a prescriptive rule in American English, commonly quoted as “‘which’ can only be used in non-essential clauses”, but the topic is rather complex, so I wrote more about it in a separate article.
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tldr: What’s written is ok, and I’ll show you what it means.
Grammar is something that falls out of the spoken language, not the written one. Punctuation is unrelated to grammar except in that rare circumstance when it signals an audible intonation change meant to alert the listener to some change in the actual underlying grammar. Those cases are hard to come up with, but do exist. All punctuation is just cues for hearing the real language in your head better.
Therefore by that metric, not only is there nothing wrong with the punctuation as written, there cannot be, and no matter how it is written.
So try saying your first example aloud in your head, which I will here write without commas because voices have no commas, just intonation:
- It’s no use repeating the obvious things that have been said by others and that can be found in any encyclopedia.
This is a restrictive that here, which you can tell because it can be substituted by which with no change in meaning or permissibility:
- It’s no use repeating the obvious things which have been said by others and which can be found in any encyclopedia.
We can’t use that in descriptive clauses but we can use both that and which in restrictive ones, so if you can swap them, you know what you have. And the other way around, too. This is grammatical whether with or without its comma:
- They always wake me at three in the morning(,) which really annoys me.
But this is ungrammatical again no matter whether you write the comma or not:
- They always wake me at three in the morning(,) *that really annoys me. [ᴡʀᴏɴɢ]
That one is wrong because it tried to use that for a descriptive clause, and you can only use which for those. The native ear goes HUH? when it hears it, which is what makes it ungrammatical.
As you see, it’s never its punctuation which makes something grammatical or ungrammatical. It’s whether you the right worms oops I mean words have managed to put together right — which this sentence almost did not. Twice. 
It had almost managed not to put the right words together, twice.
As you observe, we do not usually use commas before restrictive clauses in English because there is no intonation change to signal there. Presuming that the writer was a competent one, this means the writer was trying to signal something else by including intonation dips. I believe that what he was signalling was an apocopated version of two appositives, which I’ll use em dashes to set off with a repeated things:
- It’s no use repeating the obvious things — (things) that have been said by others — and (things) that can be found in any encyclopedia.
If you read his punctuation there, the commas, as an indicator of appositives the same way as they’re used for that in this sentence, his pauses will make much more sense. It’s not especially common, so it’s no wonder it caught your eye, but I believe that there is a legitimate reading where it makes perfect sense.
As for this one:
- “That’s the person, if I’m not mistaken, that we were talking about.”
Here you have to read this for syntactic constituents. The phrase if I’m not mistaken is a parenthetical aside. It could have been written:
- “That’s the person — if I’m not mistaken — that we were talking about.”
- “That’s the person (if I’m not mistaken) that we were talking about.”
- “That’s the person (if I’m not mistaken) who/whom we were talking about.”
So the commas are the same as parens or dashes: they’re there to surround the parenthetical statement. Since in the spoken language you cannot hear any punctuation, this cannot change the grammar. They’re just there to help the reader.
These too are all ok:
- “If I’m not mistaken, that’s the person that we were talking about.”
- “If I’m not mistaken, that’s the person we were talking about.”
- “If I’m not mistaken, that’s the person who(m) we were talking about.”
- “If I’m not mistaken, that’s the person about whom we were talking.”
- “If I’m not mistaken, that’s the person about which we were talking.”
All those are fine. About the only thing you can’t do is say:
- “If I’m not mistaken, that’s the person about *that we were talking.” [ᴡʀᴏɴɢ]
Because which cannot function there to start the clause to serve as the object of a preposition.
Summary
Don’t allow some simple, perhaps simplistic, mnemonic tip for good writing style such as “don’t use a comma before that” confuse you about the larger surrounding issues or about a sentence’s actual grammar. Such tips exist to break a common pattern in beginning writers unfamiliar with the conventions normally observed in these things. But rest assured that the actual grammar remains intact no matter the punctuation, for any grammatical error will jump out to your ear without seeing the punctuation — just like in my very last bulleted example sentence above, the one with the extra asterisk.