What each word means
There usually points to a place, or introduces a sentence. For example: The keys are over there. It can also act as a starter in sentences such as There is a new caf on the corner. In both cases, there is not showing possession or replacing a noun; it is helping the sentence move along.
Their shows possession. It tells you that something belongs to more than one person or thing. For example: The children left their coats by the door. The company changed their policy. If you can replace the word with theirs, you are probably using it correctly.
They're is a contraction of they are. It is simply a shorter form of two words. For example: They're arriving at noon. They're excited about the trip. If you can expand it to they are, then they're is the right choice.
How to tell them apart in a sentence
A useful way to decide is to ask what the word is doing. Is it pointing somewhere, showing ownership, or standing for they are? That question solves most confusion. For example: Put the box over there. The box belongs to their neighbour. They're putting the box away.
Read the sentence aloud and try swapping in the full phrase. If they are fits naturally, use they're. If the sentence talks about belonging, use their. If the sentence refers to a location or introduces something, use there.
Compare these examples carefully: There is a message on your desk. Their message was urgent. They're sending another message this afternoon. The meaning changes completely, even though the words sound identical when spoken.
A memorable trick for choosing the right one
One of the easiest memory tricks is to notice the word their. It contains the word heir, and an heir inherits or receives something. That can help you remember that their is about possession or belonging. For example: Their dog is very friendly. Their house needs a new roof.
For there, think of the phrase here and there. Both words relate to place. There often answers the question where? For example: The train station is over there. Leave the parcel there, please.
For they're, remember the apostrophe stands for missing letters. It replaces the a in are. So they're means they are, just as I'm means I am and don't means do not. If you can say they are, the apostrophe form is usually correct.
Common mistakes and how to avoid them
A very common error is using there when the sentence needs a possessive. For example, The students forgot there books is wrong because books belong to the students. The correct sentence is The students forgot their books.
Another frequent mistake is using their or there when the writer means they are. For example, Their going home now is incorrect if the meaning is they are going home now. The correct form is They're going home now.
Some people also overuse there at the start of a sentence because it sounds natural. But sound alone is not enough. In the sentence There planning a surprise party, the correct word is They're, because it means they are. Always check the meaning, not just the sound.
Practice examples you can copy
Use these model sentences to train your eye. There is a cat on the wall. Their cat is on the wall. They're watching the cat from the garden. The structure is the same each time, but the meaning changes.
Try another set: There are two emails in my inbox. Their emails arrived first. They're replying later. Again, there tells you about existence or location, their shows ownership, and they're means they are.
A final set: Put your bag over there. I borrowed their bag yesterday. They're looking for it now. If you practise sentences like these, the correct choice will start to feel automatic.
A quick self-check before you write
Before you finish a sentence, pause and ask three questions. Is it about a place or existence? Use there. Is it about belonging? Use their. Can you expand it to they are? Use they're.
This simple check is especially useful in messages, where mistakes happen quickly. For example, I left my scarf there, Their coming too, and They're ready now all need different forms. A few extra seconds of checking can save you from a very visible error.
If you are still unsure, replace the word with a longer version. If the sentence still works with they are, then they're is right. If not, it is probably there or their. With a little practice, the choice becomes fast and reliable.
Frequently asked questions
What is the easiest way to remember there, their and they're?
Think of there as place, their as possession, and they're as they are. That three-part rule solves most mistakes quickly.
Can there ever show possession?
No. There is used for place, existence, or as a sentence opener, but it does not show ownership.
Why is they're often confused with their?
They sound the same when spoken, so the difference is only visible in writing. The apostrophe in they're is the key clue that it means they are.
Is it acceptable to use contractions like they're in formal writing?
Usually yes, especially in modern British and general English. If the tone is very formal or academic, you can use they are instead.