Possessive pronouns and possessive forms show ownership, belonging, or a close connection. They tell us who a thing belongs to, who is connected to a place, or whose idea, voice, or problem something is. In the sentence The keys are on the table, the keys are mentioned, but we do not know whose they are. In My keys are on the table, my gives that missing information. Possessive forms answer questions like Whose book? Whose house? Whose phone?

Before a noun, English uses possessive determiners: my, your, his, her, its, our, their. They always come directly before the noun they modify: my car, your bag, her office, our neighbors, their children. The noun stays in its normal form after the possessive determiner, so we say my friend, not my friends unless the noun is truly plural. These forms act like an adjective in the sentence, giving the noun a possessor. His can go before a noun, as in his jacket. Its is the possessive form for something non-human, as in its tail or its owner.

Possessive determiners before nouns

Idea
Use my to show that something belongs to the speaker.
Use your to show that something belongs to the person you are speaking to.
Use his to show that something belongs to a man or boy.
Use her to show that something belongs to a woman or girl.
Use its to show that something belongs to an animal or a thing.
Use our to show that something belongs to the speaker and other people.
Use their to show that something belongs to other people.

When the noun is already known, English can replace the whole noun phrase with a stand-alone possessive pronoun: mine, yours, his, hers, ours, theirs. These words do not come before a noun. They stand alone and point back to something mentioned before or understood from the situation. Compare That is my notebook with That notebook is mine. In the second sentence, mine replaces my notebook. The same pattern works with all the forms: yours, ours, and theirs. His is the same form before a noun and by itself, but hers is used only as a stand-alone pronoun.

Replacing a noun phrase

Usage	Explanation
Ownership already clear	Use mine when the noun is understood and you do not want to repeat it.
Direct answer	Use yours to answer a question when the thing belongs to the listener.
Shared belonging	Use ours when the thing belongs to the speaker and other people.
Belonging to other people	Use theirs when the thing belongs to other people and the noun is not repeated.

The form changes with the possessor, not with the thing possessed. Use my before a noun and mine alone, so my coat becomes The coat is mine. Use we for the subject, our before a noun, and ours alone: our apartment, The apartment is ours. For plural people, their is the possessive determiner and theirs is the stand-alone pronoun: their seats, The seats are theirs. The choice depends on the job the word does in the sentence. Before a noun, use the determiner form. Alone, use the pronoun form.

Choosing possessive forms by person

Idea
Use my before a noun, but use mine when the noun is not repeated.
Use our before a noun, but use ours when the noun is not repeated.
Use their before a noun, but use theirs when the noun is not repeated.

Do not confuse your and you're. Your shows possession: your phone. You're is short for you are: You're late. Do not confuse its and it's. Its shows possession: the dog chased its tail. It's is short for it is or it has. Do not add a second noun after a possessive determiner. Say my car, not my car idea when you mean one idea that belongs to me. If the noun is already there, the stand-alone form replaces it: That is my car becomes That car is mine.

Frequent possessive errors to avoid

Idea
Use your for possession and you're only as a short form of you are.
Use its for possession and it's only as a short form of it is.
Do not add a noun after a possessive determiner when the noun is already included.

His and hers depend on the person who owns something. Use his for a male possessor: That is his seat. Use hers for a female possessor: That is hers. Its is the possessive form for non-human things, animals when the sex is not relevant, and ideas or organizations: The robot moved its arm, The company changed its policy. Unlike his and her, its never refers to a person. When the possessor is human, choose his, her, our, your, or their instead.

Gender and non human possession

Idea
Use his for something that belongs to a male person.
Use hers for something that belongs to a female person.
Use its for something that belongs to a non human thing or an animal.

Stand-alone possessive pronouns often appear after the verb be: This scarf is mine, The blue one is hers, The bigger house is theirs. They also appear after verbs such as have: I have mine already, They have theirs on the table. In spoken English, they can follow prepositions too: The seat next to yours is empty, We sat behind theirs. The stand-alone form replaces the whole noun phrase, so nothing comes after it. Say That one is ours, not That one is ours car.

Sentence positions for stand alone forms

Usage	Explanation
After be	Use a stand alone possessive pronoun after be when you identify who owns something.
After have	Use a stand alone possessive pronoun after have when the meaning is already clear.
In short replies	Use a stand alone possessive pronoun in a short answer when you want to avoid repeating the noun.

English normally shows possession without of when a possessive pronoun or possessive determiner is used. Say my friend, our house, theirs, not friend of mine in ordinary direct possession. The form of mine, of yours, of hers, of his, of ours, of theirs exists, but it is used after another noun phrase: a friend of mine, two books of hers, a neighbor of theirs. In normal possession, the possessive form stands next to the noun or stands alone by itself. Do not add of after a possessive determiner in simple sentences.

Standard possessive form without of

Idea
Use my book, not book of me, in normal English.
Use our house, not house of us, in normal English.
Use theirs for possession without of in normal speech and writing.