Grammar Rules: That and Which

grammar rules that and which

Get the grammar rules for using that and which.

There’s a lot of confusion about that and which. These two words are often used interchangeably, even though they’re not necessarily interchangeable.

Historically, that and which may have carried the same meaning, and some English dialects may allow for that and which to be swapped without affecting the meaning of a sentence.

However, in American English, the grammar rules offer a distinct difference between the two words. By the time you’re done reading this post, you’ll fully understand the difference between that and which, and you’ll be able to use both words correctly.

That and Which

As with most grammar rules, there are exceptions and exemptions from the standard ways that and which should be used in a sentence. To gain understanding of confusing word pairs, it’s always best to start with the basics. As we look at how to properly use that and which, we’ll focus on simple, standard usage.

That and which can be categorized into several different parts of speech. Both words can function as adjectives and pronouns. Additionally, that can serve as a conjunction and as an adverb. Today, we’re looking at how that and which should be used when they are working as relative pronouns.

Relative Pronouns

From Wikipedia: “A relative pronoun is a pronoun that marks a relative clause within a larger sentence. It is called a relative pronoun because it relates to the word that it modifies.”

Like adjectives and adverbs, relative pronouns modify other words. Adjectives modify nouns:

  • I have a car.
  • I have a red car.

Adverbs modify verbs:

  • I am walking.
  • I am walking quickly.

The main difference between adjectives and adverbs is that adjectives usually modify things (nouns) while adverbs modify actions (verbs). Relative pronouns also modify words, but they often do so as clauses rather than as single, descriptive words. In the examples below, the clauses are italicized.

  • Bring me the bucket.
  • Bring me the bucket that has apples in it.
  • The bucket, which has apples in it, is blue.

The difference between the words that and which and how they are used as relative pronouns depends on whether the clause they belong to is restrictive or nonrestrictive.

Restrictive and Nonrestrictive Clauses

Restrictive Clauses Are Necessary

A restrictive clause is necessary to the meaning of a sentence. For example:

  • I want the bucket that has apples in it.

If you removed the clause “that has apples in it,” the meaning of the sentence would be lost. Nobody would know which bucket the speaker wants. The clause is necessary to the meaning of the sentence and is therefore a restrictive clause. Because it’s a restrictive clause, it should take the relative pronoun that.

Nonrestrictive Clauses are Unnecessary

A nonrestrictive clause is not necessary to the meaning of a sentence. In fact, it can be removed from a sentence without affecting its meaning. For example:

  • The bucket, which is blue, has apples in it.
  • There are apples in the bucket, which is blue.

If you removed the nonrestrictive clause “which is blue,” from either of the sentences above, the meaning of the sentences would not be lost. We’d still know that the bucket has apples in it. Note that in the second example, the nonrestrictive clause adds information about something that has already been identified. Because the clause is unnecessary to the meaning of the sentence, we know it’s a nonrestrictive clause, and therefore should take the relative pronoun which.

  • Use that before a restrictive clause.
  • Use which before a nonrestrictive clause.

The Easy Way to Remember the Difference Between That and Which

I Needed That

If you need the clause to maintain a sentence’s meaning, then use that. A quick trick for remembering this grammar rule is the phrase “I needed that.”


Because which is also an interrogative pronoun used to mark questions, it is questionable. You can take it or leave it. It’s not necessary. Think of the word which with a question mark (which?) to remind yourself that if the clause’s presence is questionable and can be removed, then you should use the word which to introduce the clause.

Exceptions and Notes

Here are some exceptions and notes to these rules:

  • Which can be used restrictively when it’s preceded by a preposition. For example, “The bucket in which the apples have been stored is blue.”
  • Which is almost always preceded by a comma, parenthesis, or a dash.
  • In British English, there is little distinction between that and which.

Has this article helped clarify any questions you’ve had about grammar rules? Do you have any other questions about that and which? Do you have any tips to share for remembering how to use these two words? Leave a comment.


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About Melissa Donovan
Melissa Donovan is a website designer and copywriter. She writes fiction and poetry and is the founder and editor of Writing Forward, a blog packed with creative writing tips and ideas.


43 Responses to “Grammar Rules: That and Which”

  1. Kate Yowein says:

    What a great grammar teacher you’d be, Twinnie. My Chinese students will surely eat this up.

  2. Cath Lawson says:

    Hi Melissa – Thanks for this. I think you must be a mind reader, as I struggle with choosing between “that and which” and I’ve been thinking about it recently.

    I will try to remember this but it’s tough. I write in British English but many of my readers are American.

    • The British vs. American English is a tricky problem online. It looks to me like most people lean toward American grammar, and I have to admit I’m a little biased toward it myself…I have noticed “that and which” used interchangeably in print publications (particularly in a novel I’m reading right now, which inspired this post) and I always wonder if the writer or editor might be British. In any case, it’s good for Americans and British people to learn each other’s rules so we don’t assume errors where there are none.

  3. Martin - Writing Prompts says:

    Thanks a lot for the post. I’d never really known the rules here and so, have been abusing this grammar rule for a while. I had never realized how simple the difference was and will be telling people “I needed that” for a while now :).

    • Yeah, I like that trick for remembering: “I needed that.” Just remember that this isn’t universal and “that and which” are used interchangeably in Britain. It’s also fun learning these grammar terms, like “relative pronoun” and “restrictive clause.” Mind boggling at times, but good stuff.

  4. The article helped me a lot – it proves me i made the right move when asked for help regarding grammar and style on my blog.
    Oh my…. i am happy so much i have a friend who’s native American speaker 😉 – he helps me TONS.

    • When I was studying French, I was always confused by words with similar meanings and words that sounded the same. Darn those confusing word pairs! I never had a native French speaker friend, and by now I’ve probably lost most of the language, especially since I never had a good chance to use it (like a trip to Paris). You’re lucky to have that friend, and you’re doing quite well writing in English.

  5. Marelisa says:

    Hi Melissa: It´s amazing how much I rely on how things sound to figure out which words I need to use. I don’t have trouble choosing between “that” and “which” but I wouldn’t have been able to give an explanation as to why one or the other would be the right choice in a particular sentence (until reading this post that is 🙂 ).

    • I find that many of my good grammar habits come from reading a lot. I also find that I’ve picked up a few not-so-good habits by relying on reading to teach me the rules. That’s one of the reasons I like writing articles like this; I can really cement my understanding of how to properly use the language, and it helps me feel more confident. Interestingly, that confidence comes in most handily when I’m breaking the rules rather than following them.

  6. --Deb says:

    I always love posts like this–both reading them, and writing them! And this is a good one, so thanks, Melissa!

  7. Evelyn Lim says:

    I definitely need to revisit my grammar lessons. Now that I am writing online, it will be so embarrassing to publish articles that are full of errors. Thanks for pointing out how to use “that” and “which”!!

    • I do find that sometimes a particular phrase or sentence works better when you throw out the rules completely – but you have to know the rules before you do that. Some people don’t like learning grammar, but I think it’s fun. I’m a word nerd.

  8. Kelvin Kao says:

    When I was learning English in middle school, which was in Taiwan, (see how I just used that word?) we were taught to:

    Use “which” with commas for nonrestrictive:
    I delivered the package, which was quite heavy, to Mary.

    Use “which” or “that” without commas for restrictive:
    I only want the pancake that has ice cream on it.
    I only want the pancake which has ice cream on it.

    After 10 years in the United States, I’ve already gotten used to the usages that you mentioned in the post, and what I described above now sound a little weird to me. Then again, Taiwan is not an English-speaking country, so I’m not sure where these rules came from.

    • Look at you! Nice use of “which.” I used to think these words were interchangeable too, and I made my choice based on how each sentence sounded. But now use of “which” in a restrictive clause just sounds wrong to me. I will say that after writing this post I started coming up with a bunch of example sentences that could go either way – restrictive or nonrestrictive – and they had my head spinning.

    • Kelvin, it may be because in British English there is no distinction between “that” and “which,” and many other countries teach British rather than American English.

      • Kelvin Kao says:

        It’s interesting. I think what we were taught was a mix.
        For example, for the word that I’ve just used, “taught”, I was taught to pronounce the dark ‘o’ sound instead of saying it like “tot”. For spelling, though, we were taught the American system (color instead of colour). And we also used IPA (International Phonetic Alphabet).

        • That’s funny, because the reason I know British English is often taught throughout the world is that I once had an immigrant boss whose (American) English (including pronunciation) was spot-on except for one word. Of course, that word escapes me now, but he said it with a British accent. Before he uttered that word, I had no idea he’d only been in the U.S. for less than a decade! That launched a conversation about English being taught, and American vs. British English, and I started looking into it and found out that a lot of other countries go by British English. I guess some use a mix of the two.

  9. Marc - WelshScribe says:

    This is a very nice writeup on a particular bit of grammar that is not easy to teach. Nice work Melissa.

    I tend to agree with your earlier comment/reply to Cath, I too tend to be biased towards the American English distinction (despite being British!)

    • Thanks, Marc. I’m not sure why American English has dominated the web. I would have guessed British English to take precedence because it’s older and taught more widely.

      • Kelvin Kao says:

        That’s easy: because the internet started in the United States. The big (and first) initial content providers and search engines are U.S.-based. They have bigger control over domain names as well. Also, the ratio of English and Spanish pages is not representative of the size of English and Spanish population.

        • Steve Adams says:

          Not true. The founder of the internet was English, therefore it makes sense that English, not american English is it’s language. Notice that I didn’t say “British English” since that is a nonsensical phrase. English IS British. american English is americanised English.

          Furthermore, the slow americanisation of the English language (thankfully now in reverse in England) debases the language to the point of absurdity in some cases.

          Whenever I hear an american say “I know a couple reasons” instead of “I know a couple OF reasons” it makes me cringe. Also, why use “I have something” instead of “I have got something”. The correct usage is “I have got”, not “I have”.

          If you are going to steal a language, at least have some respect for it.

        • You seem to be saying that England holds some kind of copyright on the English language and we Americans are intentionally stealing and debasing it. You might do some research on the history of the English language as you will find that British English has roots in older languages that it “stole and debased.”

          You also seem to be saying that the founder of the Internet was English so everyone on the Internet should use British English? Would you like to legislate that?

          I love how you don’t capitalize American; that says a lot.

  10. Karen Swim says:

    Melissa I have been enjoying your posts in my email but failing to make it over to chat but this is a post that I could not resist offering a public kudos.:-) I love the “I needed that.” We all need to keep our grammar skills fresh and you do an incredible job of presenting the information for writers and non-writers.

    • Karen, I’ve been enjoying your posts in my RSS reader. I guess this is a busy time of year for everyone, because I just haven’t been making my comment rounds. Thanks so much for your kind words. Like I always say, “Grammar is fun!” (and useful).

  11. Bobby Revell says:

    As always, lots of great tips here. One of my favorite things to do is use adverbs to describe nouns and adjectives to describe verbs—or treat verbs as nouns. I know it’s incorrect, but if used in certain ways, it can be effective in creating unique phrases. These days, I try to avoid thinking theoretically. To me, creating unique phrasing is one of the most difficult aspect in writing. I think like this: there are millions of guitar players who can play the blues and most sound the same. When you hear someone like Jimi Hendrix, you know it’s him even if you only hear one small fragment—it’s so unique in voice it cannot be denied. That’s the type of writer I want to be. You read one sentence and know who it is. Without knowing the rules of grammar and all the theory, it will be next to impossible to achieve a unique voice.

    • I like the idea of switching up adverbs and adjectives. Very clever. You’re right; establishing voice is a definite challenge for writers and all artists. Did you know that to get into some MFA literary programs, they actually test you on that — identifying authors through short excerpts of their work, and you have to be able to recognize their voice (unless you’ve memorized the entire canon)?

  12. Alex F. Fayle says:

    Great post about the distinctions.

    Ever since I started teaching English I’ve become much more aware of how I use language – this is a great example of something I’ve never thought about. Thank you!

    • Alex, I had no idea you taught English. If I wasn’t so averse to public speaking, I’d probably be doing the same. Or maybe I’d teach creative writing…Anyway, keep sharing grammar with your students, and thank you for being a teacher.

  13. Iain Broome says:

    I think all writers have that one ‘thing’ that they always have to check or remind themselves about. This is mine. Thank you. Bookmarked for future and no doubt regular reference.

  14. Steve says:

    I came across your site and was delighted to find such a cornucopia of writing tips and grammar explanations. I have added you to my favourites and begun following you on Twitter. I too recently blogged on the subject of “which” and “that”.

    Contrary to possible arising suspicions of plagiarism, my blog was intended for learners of English as a second language and I didn’t discover your contribution until after mine had been written. You can see it here:

    I know it’s been touched on in the comments here before but I just felt I should point out that “which” and “that” are not generally considered interchangable in British English as you state, except in non-defining clauses where both are acceptable.

    I can say with confidence that the Cambridge ESOL examining board test students’ understanding of this in their FCE and CAE exams, and mark according to the principle I mention above.

    I tend to stress to my weaker students that “which” is ALWAYS acceptable as a relative pronoun for inanimate objects in subordinate clauses, while usage of “that”, while more common in spoken English, requires special attention.

    Thanks so much for opening up the debate. Grammarians like myself thrive on these very nuances that make us wonder at the complexity of our language!

  15. Thank you so much for the light…

    Someone is Special

  16. Farhad says:

    Hello Melissa

    Thank you for this article; it is very helpful.

    I have realised that there are certain differences between recommendations given by The Chicago Manual of Style and the Oxford Style Manual, which is British. Rules for the use of semicolon, for example, is different in British English, (see my opening sentence) from the American English.

    I am slightly confused as which manual of style should I use, the British or the American?

    Kind regards


    • It depends on the audience for which you’re writing. If you’re writing for British publication, you would use British English and a British style guide. It gets tricky when you’re writing for the Internet because then you’re dealing with an international audience. I think online, most writers simply go with their native language (British or American English) or they might choose whichever they think is more suited to their audience.

  17. Preity says:

    Hey Melissa, thanks for this post. I used to hold a big confusion regarding the duo (that and which) that has now been cleared. One thing I want to know is, do we use any punctuation mark like comma before “that” or not. Plz do help!

  18. David says:

    This is awesome. Thank you for sharing your knowledge and helping make things clearer. I have recently found writing to be a joy and any information that makes it better is so appreciated.
    Thank you,
    David Mors

  19. Spring and Autumn says:

    Nice post, though I must gently protest as regards the absence of “which” in restrictive clauses. “Which” is proper usage and, in many cases, can be very much preferable.

    The usage of which, in British English at least, often sounds much more erudite than ‘that’. It is a matter of style and you will find that all the great English (from England) authors stretching right back to Chaucer (included) use both without hesitation, sometimes within the same paragraph.

    The King James Bible reads as follows, ”Behold the blood of the covenant which the Lord hath made with you.”

    ‘That”, in the above sentence, would subtract something from the overall effect of the text, IMO.

    The new American style rule (I say new as it seems to be a relatively recent invention) is useful for simple examples, but I find it far too constricting, and, indeed, possibly fatal to great writing.

    • I mentioned at the beginning of the post that it covered American English usage, and our official grammar frowns upon “which” in restrictive clauses in most cases.

      Regardless of whether we write or speak British or American English, the entire language and its grammar has changed dramatically since the days of King James.

      I think there is a lot of wiggle room with “that” and “which” but I actually prefer them to have distinct definitions and applications.