Who's vs. Whose: Which is which, and when to use them

A common written grammatical mistakes is the misuse of who's and whose. This is partially understandable since the two words are pronounced the same way (HOOZ, as in "blues" or "lose"). But we are concerned with writing. So, which is which? What are their grammatical functions, and when can you use them? In this article, we are going to improve our written grammatical accuracy by learning the difference between these two commonly confused words, and by seeing them in relevant contexts.

In short:

Who's is the contracted form of "who is," or "who has" when it is being used in the present perfect or present perfect continuous form. Whose is a possessive pronoun, meaning it stands in for the possessor of an object--it asks or shows whom or what something belongs to, or whom or what someone or something is related to.

Here are five quick examples to show the difference:

"Who's going to the game with you?" (Who is going to the game with you?)

"Marta, who's worked on things like this before, is the best fit for this project." (Marta, who has worked on things like this before, is the best fit for this project.)

"Who's been using my computer today?" (Who has been using my computer today?)

"Whose backpack is this?" (Who(m) does this backpack belong to?)

"I have no idea whose idea this was." (I have no idea who possessed and came up with the idea in the first place.)

Now, let's explain the differences in greater detail, and take a look at more example sentences to clarify and illustrate the distinction.

"Who's" as "who is"

You can ask questions, or you can begin relative clauses with who's to give more information about a subject. These uses make sense because "who" is an interrogative or a relative pronoun depending on the context. The best way to learn grammatical functions is to see them in action, so let's take a look at some examples, and their uncontracted forms.

"Who's there?" (Who is there?)

"Breanne, who's the nicest person you could ever hope to meet, is going to drive for three hours just to attend my birthday party." (Breanne, who is the nicest person you could ever hope to meet,...)

"Mark's the guy who's always messaging me at work." (Mark is the guy who is always messaging me at work.)

"Who's that?" (Who is that?)

"I don't know who's coming." (I don't know who is coming.)

"Do you know who's responsible for this?" (Do you know who is responsible for this?)

"Who's going out for lunch today?" (Who is going out for lunch today?)

"We have no idea who's going to come." (We have no idea who is going to come.)

"You think I should be fired? I'm not the one who's always coming in late." (You think I should be fired? I am not the one who is always coming in late.)

"Who's in charge here?" (Who is in charge here?)

"This report doesn't take into account who's eligible for the program and who isn't." (This report does not take into account who is eligible for the program and who is not.)

"Who's ready?" (Who is ready?)

As you can see, there are many ways to use who's. Just remember that it is a contraction, and that contractions use apostrophes to signify one or more missing letters. In the "who's" examples above, the missing letter is i, as in "who is". If you can remember the function of contractions, you're already on your way to better, more accurate writing.

Now, let's continue.

"Who's" as "Who has"

Use this form to introduce a present perfect or present perfect continuous relative clause that gives more information about someone, or which introduces a present perfect or present perfect continuous question that refers to a person. If you're not familiar with the present perfect, it is what you use when you say things like "I haven't started my essay yet," "She has lived here for ten years," or "We have never been to Ottawa." The present perfect continuous is used in sentences such as these: "The company has been losing money for six months"; "I've been waiting here for thirty minutes"; "They have been talking all morning." Let's take a look at how the present perfect and present perfect continuous can be used in questions and relative clauses:

"Who's been using my phone?" (Who has been using my phone?)

"Who's seen the latest Batman movie?" (Who has seen the latest Batman movie?)

"This is the Tim. He's the one who's been waiting for 2 hours." (This is Tim. He is the one who has been waiting for two hours.)

"Do you know Vicky?"

"I think so. Is she the one who's recently had a car accident?" (Is she the one who has recently had a car accident?)

"I'm not the person who's been lying the entire time!" (I am not the person who has been lying the entire time!)

"Haha. Very funny. Who's taken my stapler?" (Haha. Very funny. Who has taken my stapler?)

"Who's been married longer? You and Diana, or Sam and Tina?" (Who has been married longer? You and Diana, or Sam and Tina?)

"Giovanna, who's been here since February, still doesn't know how to use the software." (Giovanna, who has been here since February, still does not know how to use the software.)

"He's someone who's gone through a lot." (He is someone who has gone through a lot.)

"The contestant who's gotten the most points by the end of the game, wins." (The contestant who has gotten the most points by the end of the game, wins.)

"Who's been in my room?" (Who has been in my room?)

"I've been thinking a lot about who's been included and who's been excluded from the list." (I have been thinking a lot about who has been included and who has been excluded from the list.)

Has this made things clearer for you? I hope so! Finally, let's move on to the uses of whose.

Whose

"Whose" is linked to possession. It refers to the person (or place!) whom something belongs to. If you say "Whose phone is this?", you mean "To whom does this phone belong?" Yes, that sounds formal, and it's why we use "whose" instead in most situations. You can also use it to refer to whom someone is related to (see the examples below). Finally, just like "who's," you can use "whose" to ask questions, or to set off relative clauses. Okay. Let's take a look at some sentences:

"Whose phone is this?" (Who(m) does this phone belong to?)

"Do you know whose this is?" (Do you know whom this belongs to?)

"She's the one whose car was stolen."

"I don't know whose jacket this is."

"There's a notebook on the table."

"Whose is it?" (Who(m) does it belong to?)

"You'll never guess whose house this is."

"Asuka, whose mother is a dentist, is studying dentistry."

"I need someone's phone. I don't care whose!"

"Do you remember whose class we took together in college?"

"Remember when I told you about Jim? This is him! He's the guy whose uncle was in the army."

"We never found out whose dog it was that we saw by the lake."

"The best teacher is the one whose students learn from."

"That's the building whose offices were destroyed in a fire last month."

The last example might sound funny, but English does not have a possessive equivalent to "whose" for non-human subjects, so it's completely fine to say "whose" in this case.

And that's it! Those are the differences and uses of who's and whose. I hope you feel more confident using them moving forward. To practice, why don't you write some sentences in the comments? Try writing five original sentences for each usage, meaning who's as "who is," who's and "who has," and whose. I'm looking forward to reading your examples.

If you have read this far, you have probably enjoyed reading this article. If you would like to continue improving your English, or if you would simply like to support my work, consider purchasing one of my books. Thank you, and I wish you success in your studies.