Do you use “which” and “that” as interchangeable words in sentences because they mean the same?
That couldn't be further from the truth. We're here to help you determine when to use each word.
- Of course, there's a trick:
- If your sentence has a clause but does not need it, use “which”; if the sentence does need the clause, use “that.”
- That's simple, right?
The clause that comes after the word “which” or “that” is the determining factor in deciding which one to use. If the clause is absolutely pertinent to the meaning of the sentence, you use “that.”
If you could drop the clause and leave the meaning of the sentence intact, use “which.”
To drop some technical terms, “which” and “that” are relative pronouns that begin adjective clauses, which are clauses that tell us a little more about the noun they follow. The clauses that start with “that” are called restrictive because they tell us ONLY about the noun being discussed.
The “which” clause is non-essential or non-restrictive, and as such, is always set off from the rest of the sentence with commas.
- The old schoolhouse, which is one of my favorite historical sites to visit, is in dire need of renovation.
In this case, you could drop the clause “which is one of my favorite historical sites to visit” and the sentence still makes sense:
- The old schoolhouse is in dire need of renovation.
On the flip side, try this example:
- The type of antibiotic that the doctor prescribed made me nauseous.
Clearly, it's not just any antibiotic, but the one the doctor prescribed that made you sick to your stomach. The sentence without the clause doesn't make sense:
- The type of antibiotic made me nauseous.
- The building, which towered over the sightseers, gave me the shivers.
- The building that towered over the sightseers gave me the shivers.
That vs. Which
One of our readers, Justin, recently wrote to ask:
When proofreading a peer’s article on the solar system, I realized that she, and I, are unsure of the proper use of “that” and “which” in a sentence. Below is [SIC] two examples of the same sentence, one using “that” and the other “which.”
- “To our knowledge, it is the only body in the solar system which currently sustains life, although several other bodies are under investigation.”
- “To our knowledge, it is the only body in the solar system that currently sustains life, although several other bodies are under investigation.”
Which is the correct sentence, and what is the general rule of thumb?
Justin, I’ll give you the answer now, rather than making you read to the end of the whole article: the second version of that sentence, using that is correct.
When To Use “That” and When To Use “Which”
Before I come on to the “that”/”which” rule, just a reminder that “who” should always be used when referring to people.
- The boy who threw the ball.
- This is the woman who always wears a black shawl.
When referring to objects, though, the rule for using “that” and “which” correctly is simple:
- THAT should be used to introduce a restrictive clause.
- WHICH should be used to introduce a non-restrictive or parenthetical clause.
If that leaves you more confused than when you began this article, read on…
A restrictive clause is one which is essential to the meaning of a sentence – if it’s removed, the meaning of the sentence will change. For example:
- Chairs that don’t have cushions are uncomfortable to sit on.
- Card games that involve betting money should not be played in school.
- To our knowledge, it is the only body in the solar system that currently sustains life…
A non-restrictive clause can be left out without changing the meaning of a sentence. Non-restrictive clauses are either in brackets or have a comma before and after them (or only before them if they come at the end of a sentence):
- Chairs, which are found in many places of work, are often uncomfortable to sit on.
- I sat on an uncomfortable chair, which was in my office.
Why You Need to Use “That” or “Which” Correctly
Changing that to which or vice versa can completely change the meaning of a sentence. Consider the following examples:
- My car that is blue goes very fast.
- My car, which is blue, goes very fast.
The first sentence uses that – suggesting I own more than one car (and even implying my other cars might not be so fast). This is what happens if we leave out the clause and write:
- My car that is blue goes very fast.
- My car goes very fast.
The sentence’s meaning has changed: the reader does not know which one of my cars goes very fast.
However, the sentence using which simply informs the reader that my car is blue. We can take the clause out without losing any essential information:
- My car, which is blue, goes very fast.
- My car goes very fast.
“That” and “Which” in Common Usage
It is common today for which to be used with both non-restrictive and restrictive clauses, especially in informal contexts:
- Who ate the cake that I bought this morning?
- Who ate the cake which I bought this morning?
The clause “that I bought this morning” is essential to the meaning – I’m not asking about a cake which I bought yesterday, or this afternoon. Therefore, the first example using “that” is the correct one, but many people would not consider the second ungrammatical.
It is, however, incorrect even in informal contexts to use that for a non-restrictive or parenthical clause. For example, these sentences would be considered incorrect:
That vs. Which
The standard rule of grammar is that the usage of that vs. which depends upon whether the following clause is restrictive or non-restrictive.
“That” is used to indicate a specific object, item, person, condition, etc., while “which” is used to add information to objects, items, people, situations, etc. Because “which” indicates a non-restrictive (optional) clause, it is usually set off by commas before “which” and at the end of the clause.
The general rule requires that you use that only to introduce a restrictive (or defining) relative clause, which identifies the person or thing being talked about. For example,
The building that I was telling you about is just down the road.
In this sentence, the phrase that I was telling you about specifically identifies the object in the previous phrase (building) and is a restrictive clause. In this use, that should never be preceded by a comma because the word is an integral (non-optional) part of the description.
Similar examples include:
- My books that have red covers are new.
- The classes that are held every Monday start at 9:00 AM.
Note that the subject of the restrictive clause can change “that” to “who”, “when” and “where” for correct usage. Use who for a person, when for a time period and where as a substitute for “that place”. For example:
- The man who shot Lincoln jumped onto the theater's stage.
- Remember the time when I fell off the ladder?
- Billy went to where they sell turkey eggs.
Rule for using Which instead of That
On the other hand, use which with non-restrictive (or non-defining) clauses. These are clauses providing additional information about something that has already been identified in the context. In this use, which is always preceded by a comma and a comma is placed after the restrictive clause ends (if the sentence continues). For example,
- My new books, which have black covers, are on the desk.
- The padded chairs, which are on the second floor, have to be replaced.
When the clause is at the end of the sentence, only one comma is used, before which:
The students in Chemistry 101 have been complaining about the textbook, which is hard to follow.
In this case, the clause which is hard to follow is descriptive, not restrictive i.e. it does not specify which text is being complained about (although it can be easily inferred). For these cases, which sounds more natural than that.
Some grammarians extend the rule and insist on that being used only in restrictive clauses, while which should be used only in nonrestrictive clauses. For example:
Wrong, according to strict grammarians: I need a book which will tell me all about city gardening.
Correct usage: I need a book that will tell me all about city gardening.
The use of which with restrictive clauses is fairly common, even in edited prose. However, the American Psychological Association (APA), in its 6th edition Manual, recommends adhering to the rule and use that for all restrictive clauses.
Which can be especially useful where two or more relative clauses are joined by and or or. For example,
Politics is an environment in which ordinary people may succumb to greed and which many have found reason to hate.
You may also want to use which to introduce a restrictive clause when the preceding phrase contains a that or a those. For example,
- We want to fund only those initiatives which will increase revenues and customer satisfaction.
Which or That? | Get It Write Online
While both which and that can be used in other constructions, the confusion usually arises when they are being used as relative pronouns to introduce adjective (or relative) clauses. In the examples below, we have bracketed the adjective clauses. (Remember that a clause is simply a group of words containing a subject and a verb.):
- Our house [that has a red door and green shutters] needs painting.
- Our house, [which has a red door and green shutters], needs painting.
- The classrooms [that were painted over the summer] are bright and cheerful.
- The classrooms, [which were painted over the summer], are bright and cheerful.
In all four cases, the adjective clause tells us something about either the house or the classrooms, but the choice of which or that changes the way we should read each sentence.
How They Differ in Meaning
In the first sentence, the use of that suggests that we own more than one house and therefore must explain to you that we are talking about a particular house of ours—the one with a red door and green shutters.
We cannot leave out that adjective clause because it is essential to your understanding of the sentence; that is, you wouldn’t know which one of our houses needs the paint job without that clause, without that information.
The second sentence tells you that we own only one house and we are simply telling you—in case you want to know—that it happens to have a red door and green shutters. We could leave out the information in that adjective clause and the sentence would still make sense.
The third sentence, because it uses that to launch its adjective clause, tells us that only SOME of the classrooms were painted over the summer.
If we omitted the clause “that were painted over the summer,” we would be left with “The classrooms are bright and cheerful,” a statement that would not be accurate since it would imply that ALL the classrooms are bright and cheerful.
In this sentence, therefore, the adjective clause is essential to the meaning of the sentence.
“That” Clauses Are Restrictive/Essential
We call the adjective clauses in sentences one and three essential or restrictive because they restrict—or limit—the meaning of the nouns they modify. In the case of sentence three, they tell us that we are talking ONLY about the classrooms that were painted over the summer—not the others.
“Which” Clauses Are Nonrestrictive/Nonessential
The which clause in the fourth sentence is what we call a nonessential—or nonrestrictive—clause. Since that sentence intends to tell us that ALL the classrooms were painted, the information in the adjective clause is not essential. That is, the sentence would be clear even type if the clause were omitted.
The rule of thumb, then, is that which clauses are nonrestrictive (nonessential) while that clauses are restrictive (essential).
And They Need Commas
Nonrestrictive clauses and phrases are set off from the rest of a sentence by a pair of commas (as in our examples above) or by a single comma if they come at the end of the sentence. (Example: “I took a vacation day on my birthday, which happened to fall on a Monday this year.”)
Not Everyone Understands
Merriam-Webster’s Collegiate Dictionary, regarded by most writers as the authority on such matters, tells us that it is now common for which to be used with either kind of clause, while that must be used only for restrictive clauses. In fact, though, careful writers continue to make the distinction described above.
This Distinction Is Important in Legal Contexts
Attorneys are taught to use which for nonrestrictive clauses and that for restrictive clauses so as not to cause a misreading in legal documents. It seems just as important that we work to avoid misreadings in all writing, not only in situations when a legal ruling might be at stake.
One Final Point
Remember that we should use who and whom instead of which or that in reference to people (and animals with names, such as pets):
- These are the students who [NOT that] just finished their exams.
- Everyone who [NOT that] came to my house for dinner brought food to share.
- The technician whom [not that] I called this morning was at my house by noon.
Which pronoun—which or that—belongs in each blank below?
- Carlos gave Maria a study guide for material ________ was going to be on the test.
- Carlos gave Maria notes from chapters 3 through 7 _________ were going to be on the test.
- Mark and Sarah took their children on every vacation _________ they took to the coast.
- The teachers gave awards to all paintings ________ showed originality.
- Carlos gave Maria a study guide for material that was going to be on the test. [To say simply “Carlos gave Maria a study guide for material” would not be complete information. We need the adjective clause to tell us which material, in particular.
Since the information is, therefore, essential, we use that and no comma.]
- Carlos gave Maria notes from chapters 3 through 7, which were going to be on the test.
[The fact that chapters 3 through 7 were going to be on the test is not essential to our understanding exactly which notes Carlos gave Maria, so we use a comma and which.]
- Mark and Sarah took their children on every vacation that they took to the coast.
[If we said simply “Mark and Sarah took their children on every vacation,” we would be inaccurate. The information in the adjective clause is essential to our understanding that the children went on certain vacations and not others. Therefore, we use that and no comma.
- The teachers gave awards to all paintings that showed originality. [To say simply “The teachers gave awards to all paintings” would be inaccurate. The information in the adjective clause is, therefore, essential to the meaning of the sentence, so we use that and no comma.]
©2000 Get It Write. Revised 2003 and 2019.
When to Use Which or That
When to use which or that is one of the most grammatically confusing grammar lessons ever taught.
The fact that the two words are considered practically interchangeable in modern English does not make learning the distinction between the two much easier.
You could sit through four years of English classes and still not fully understand when to use “which” or “that.” Hopefully, the illustrations below will help you.
The elements up for illustration are not earth, wind or fire. Let's talk sentence elements. They are restrictive and non-restrictive elements.
- A restrictive element is a word, phrase or a clause that manages to limit the meaning of the sentence element that it modifies. When a restrictive element is not included then the entire meaning of the sentence will change.
- The non-restrictive element is a word, phrase or a clause that provides excess information about the beginning of a sentence without restricting the meaning of that part of the sentence.
Keep these two definitions in the back of your mind because they will be crucial in understanding when to use “which” or “that.”
The word “that” is considered to be a restrictive element of any sentence that it may be used in.
Look again at the definitions above – a restrictive element limits the meaning of the sentence element that it modifies. For example, in the sentence, “Baby foods that contain soybeans are best,” the restrictive element of the sentence are the words “that contain.” These words restrict the type of baby food that is being discussed.
In effect, without the words “that contain” the whole sentence meaning would be altered. In fact, there would be no restrictive element of the baby food. Instead the sentence would imply that all baby food is best.
“Which” Is Non-Restrictive
Who, That, Which
Rule 1. Who and sometimes that refer to people. That and which refer to groups or things.
Examples: Anya is the one who rescued the bird. “The Man That Got Away” is a great song with a grammatical title.
Lokua is on the team that won first place.
She belongs to a great organization, which specializes in saving endangered species.
Rule 2a. That introduces what is called an essential clause (also known as a restrictive or defining clause). Essential clauses add information that is vital to the point of the sentence.
Example: I do not trust products that claim “all natural ingredients” because this phrase can mean almost anything. We would not know the type of products being discussed without the that clause.
Rule 2b. Which introduces a nonessential clause (also known as a nonrestrictive or nondefining clause), which adds supplementary information.
Example: The product claiming “all natural ingredients,” which appeared in the Sunday newspaper, is on sale.The product is already identified. Therefore, which appeared in the Sunday newspaper is a nonessential clause containing additional, but not essential, information.
Essential clauses do not have commas introducing or surrounding them, whereas nonessential clauses are introduced or surrounded by commas.
Rule 3. If that has already appeared in a sentence, writers sometimes use which to introduce the next clause, whether it is essential or nonessential. This is done to avoid awkward formations.
Example: That which doesn't kill you makes you stronger. This sentence is far preferable to the ungainly but technically correct That that doesn't kill you makes you stronger.
The distinction between that and which, though a useful guideline, is not universally accepted as a hard-and-fast rule. For many centuries and up to the present, which has been routinely used by great writers and journalists to introduce essential clauses.
Are you ready for the quiz?
That vs. Which // Purdue Writing Lab
One of the more challenging grammar concepts in the English language is the difference between the words that and which. Both serve a similar purpose, but the meaning of the sentence can change depending on which one you use. The resource below breaks down the grammar rules associated with that and which and describes when to use each one.
Whether to use that and which depends on whether the clause it introduces is restrictive or non-restrictive. A restrictive clause means that the information in the clause is necessary to understand the preceding noun. For a restrictive clause, use that.
- Let’s look at some sample sentences:
- Example 1: Brad’s sweater [noun] that has fancy elbow pads [restrictive clause] was a birthday gift from his sister.
- In this sentence, we understand that Brad has multiple sweaters, so it’s important to distinguish the one with the fancy elbow pads from the others.
- Example 2: Laptops [noun] that are used for gaming purposes [restrictive clause] are usually more expensive.
- Here, because not all laptops are used for gaming purposes, we use that to indicate the necessary information.
- Example 3: The chair [noun] in my kitchen that has a broken leg [restrictive clause] is dangerous to sit on.
Once again, this sentence indicates there are multiple chairs in the kitchen, making it important to include a restrictive clause. Note that the restrictive clause does not necessarily need to be positioned immediately after the noun.
Use which when the information in the clause isn’t necessary to understanding the noun in the sentence. This sort of clause is a non-restrictive clause. There is one other important distinction between restrictive and non-restrictive clauses: commas are used to separate the non-restrictive clauses from the rest of the sentence.
Example 1: Stacy’s truck [noun], which is painted red [non-restrictive clause], has a dent in the back bumper.
Here, the information about Stacy’s truck being red is not necessary to the sentence. Stacy only has one truck, so the extra information doesn’t help identify it. Therefore, we use which and separate the non-restrictive clause with commas.
Example 2: Paul’s favorite café [noun], which serves excellent coffee and paninis [non-restrictive clause], is in Memphis, Tennessee.
Once again, we don’t need the information about the coffee and paninis to understand the rest of the sentence. We could omit the non-restrictive clause and still understand the sentence perfectly: “Paul’s favorite café is in Memphis, Tennessee.”
Example 3: The human heart [noun], which contains four valves [non-restrictive clause], weighs approximately eleven ounces.
In this example, because all human hearts have four valves, the descriptive clause does not provide necessary identifying information to the sentence. Thus, we use “which.”
Before we move onto some practice sentences, let’s go back and look at ALL the sentences above and see how changing whether you use that or which changes the meaning of the sentence.
Here are the sentences that used that. Let’s see what happens if we use which instead.
- Brad’s sweater that has fancy elbow pads was a birthday gift from his sister.
- Brad’s sweater, which has fancy elbow pads, was a birthday gift from his sister.
- In the second sentence, changing to which causes the sentence to imply that Brad only has one sweater.
- Laptops that are used for gaming purposes are usually more expensive.
- Laptops, which are used for gaming purposes, are usually more expensive.
Here, the sentence has changed to imply that the primary purpose of all laptops is gaming. Because not all laptops are used for gaming purposes, the sentence is not true.
- The chair in my kitchen that has a broken leg is dangerous to sit on.
- The chair in my kitchen, which has a broken leg, is dangerous to sit on.
- Once again, if we use which, the sentence implies that there is only one chair in the kitchen.
- Now let’s look at the sentences that used which and see how they change when we use that.
- Stacy’s truck, which is painted red, has a dent in the back bumper.
- Stacy’s truck that is painted red has a dent in the back bumper.
- Here, the second sentence implies that Stacy owns multiple trucks, thus making it necessary to specify the red one.
- Paul’s favorite café, which serves excellent coffee and paninis, is in Memphis, Tennessee.
- Paul’s favorite café that serves excellent coffee and paninis is in Memphis, Tennessee.
- In this example, changing which to that states that Paul is interested in many cafés that serve excellent coffee and paninis, and the sentences specifies that his favorite is in Memphis.
- The human heart, which contains four valves, weighs approximately eleven ounces.
- The human heart that contains four valves weighs approximately eleven ounces.
- Similar to an example above, this sentence becomes factually incorrect when we change it from which to that, since all human hearts contain four valves, and it’s not necessary to specify that.
Take a look at these practice sentences below and see whether they need that or which. Don’t forget that which sentences need commas, too.
- My first class on Mondays (that/which) starts at 10:30 is my chemistry lab.
- Have you heard of the new band (that/which) uses glitter cannons at their concerts?
- The new gym (that/which) has twelve racquetball courts is only five minutes from my house.
In the first sentence, we use which because it doesn’t make sense to have multiple classes starting at 10:30. This means the clause is non-restrictive.
In the second sentence, because there are many, many bands, we need to use that to specify the one we’re talking about, making it a restrictive clause.
The third sentence is a trick! Depending on what you’re trying to say, you may use either word! If there are multiple gyms five minutes from your house, you would use that to specify the one with the racquetball courts. However, if there is only one gym five minutes from your house, the clause is non-restrictive, and you would use which.
That vs. Which: How to Decide Which to Use
That or which? Which one do you use…and when?
It can get confusing, so much so that often you just chuck one in and hope it was the right choice.
And let’s let you in on a little secret: Usually you can get away with it (at least with non-copy-editor types). That’s because most other people are also a little shaky on the which vs. that concept…plus, nowadays, few people are real sticklers about it any more.
That vs. which — It can be tricky!
It makes sense. Initially that and which were used interchangeably.
Then, in the early 1900s, grammarians, most notably the Fowler brothers, decided there should be a rule about using them “correctly” and not interchangeably, and, well, that was that. (And which was which…)
The rule has now become so ingrained in modern usage that nitpickers and strict grammarians will seize on an errant that or which and think you don’t know how to write properly. (You do, of course. We’re sure of it.) Yes, even though it’s not a true crime against grammar, it’s often treated as one.
That’s why, instead of just picking one and hoping you nailed it, it helps to know the traditional that vs. which rule that so many people still adhere to. So here goes …
When to use that and when to use which: A definitive guide
Let’s start with a super-truncated version of the rule espoused by the Fowlers and many other grammarians: That and which are both used to connect a clause to a sentence. If the clause is necessary to the sentence, you use that. If it’s not, you use which.
Now for a few more details: You use that and which to connect two different kinds of clauses — essential clauses (aka restrictive, defining, or integrated relative clauses) and nonessential clauses (aka, logically, non-restrictive, non-defining, or supplementary relative clauses).
Here’s a quick breakdown of what’s what, clause-wise:
An essential clause is a clause that is, as you may have guessed, essential to the meaning of the sentence. It contains vital information about the subject of the sentence. And it’s literally an integral part of the sentence — that is, it isn’t set off by commas. Traditionally, when it’s an essential clause you use a that (or, if it’s a person, a who).
I need to get the car that is in the garage.
The clause “that is in the garage” is essential to the sentence because it tells us exactly which car I need to get. There can be other cars, but I need the specific one that’s in the garage.
A nonessential clause is, yes, not essential to the meaning of the sentence. It adds color material, information that adds texture or detail to the sentence but that isn’t ultimately necessary. It’s set off by commas and can be deleted from the sentence without having any impact on the meaning whatsoever. A nonessential clause gets a which.
I need to get the car, which is in the garage.
In this case, the clause “which is in the garage” is telling us a little more information about the car, but isn’t vital to understanding the sentence …the thrust of which is simply that I need to get the car.
There are some exceptions to the that vs. which rule!
Needless to say, since it’s English we’re talking about, there are some caveats.
Caveat #1: If there’s already a “that” in the sentence, most writers will follow up with a “which” even if it’s opening an essential clause.
Take William Shakespeare. In Romeo and Juliet, he writes: “That which we call a rose by any other name would smell as sweet.
” This is much more euphonious than the clunky (but correct) “That that we call a rose…” And if it’s good enough for Shakespeare, it’s good enough for us.
Even the grammarians who wrote the initial “here’s how to use which vs. that” thought there were times the rule could be bent.
Which leads us to caveat #2, a very important point: Nowadays most style guides, usage manuals, and dictionaries agree that, when it comes to that and which, the old rule isn’t the end all and be all anymore.
They give us quite a bit of latitude, saying we can eschew the traditional “always use that with essential clauses.” Yes, some copy editors and sticklers might disagree, but they’re fighting a losing battle.
The new general rule of thumb is simple, and makes life a bit easier:
Use which when it’s a nonessential clause…but take your choice of that or which when it’s an essential one. It’s your call — whichever you think works best stylistically.
Yes, the (grammatically pure) times are a-changing. And now, that is that…which is to say, we’re done.
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