I often see these three words – there, their, and they’re – misspelled or used interchangeably. I know they all sound the same when you’re speaking, but each has its own unique use when you are writing.
THEY’RE is the easiest to figure out how to use. Since it is short for “they are”, read your sentence aloud and substitute “they are” for “they’re, their, or there”. You’ll quickly figure out if “they’re” is the spelling you need.
For example, “they’re going to the store” is correct, since you could also write, “they are going to the store”. On the other hand, “they’re house is the biggest on the block” is not correct. You would never write or say “they are house“. Likewise, “they’re is your coffee” is not correct. To say or write “they are is your coffee” would just not make sense.
THEIR is possessive. That means it describes something belonging to two or more people. So the correct way to write our second example is “their house is the biggest on the block“. If you can substitute a name, the letter S, and an apostrophe for the word, then “their” is the spelling you need.
Let’s go through our three examples again, imagining that we are talking about John and Anne Smith. “Their going to the store” doesn’t work because we wouldn’t say or write “The Smiths’ going to the store“. (Yes, you could add the word “are” in here and then the sentence would make sense but if you are adding the word “are”, then “they’re” is the word to choose. When you are substituting to test your sentence, you only add the word “are” for “they’re”.)
“Their house is the biggest on the block” is right. The meaning is still clear if you write “The Smiths’ house is the biggest on the block.” And the last sentence, “their is your coffee” isn’t right. Why would anyone say “the Smiths’ is your coffee“?!
THERE refers to a place, either as a location or in time. A good way to think about this use is to remember that “there” is spelled like “where” and answers a “where” type of question. “Where is my coffee?” “There is your coffee” or “your coffee is over there“. Nobody is going to ask you “where house is the biggest on the block?” or “where is going to the store?”
The main thing to remember, if you want to try the substitute tests to see if you are using these words correctly, is to not add any extra words to your substitution. Only add “they are” to see if “they’re” is the correct usage. And only try “the Smiths'” when checking to see if “their” is the word you want.
Bonus tip: Note that “their” can also be used without specific names so sometimes you might have to substitute a plural noun (a word describing a group). Example: “their feed was taken to the barn.” “The cows’ feed was taken to the barn.”