How do you form a question tag in English?

Take the auxiliary from the statement, reverse the polarity, and add a pronoun. A positive statement takes a negative tag and a negative statement takes a positive one: She is late, isn't she? and She is not late, is she? If the statement has no auxiliary, borrow do, does or did: You work here, don't you?

Why do people say aren't I instead of amn't I?

Because amn't does not exist in standard English. There is no negative contraction of am, so the tag after I am borrows the plural form: I am late, aren't I? It is irregular and there is no logic to defend, you simply learn it. Am I not? is grammatically correct but sounds stiff and formal in speech.

What tag do you use after an imperative like close the door?

Imperatives do not follow the mirror rule at all, because there is no auxiliary and no subject to mirror. Use will you, won't you, would you or can you: Close the door, will you? A negative imperative takes will you as well: Don't be late, will you? And after let's the tag is always shall we: Let's start, shall we?

Does a question tag always mean you are asking a question?

No, and this is the part learners miss. If your voice falls on the tag you are not asking anything, you are inviting agreement: Lovely day, isn't it? If your voice rises you genuinely do not know the answer and want one: You locked the door, didn't you? Same words, different job, and only the intonation tells them apart.

Question tags in English: the mirror rule, aren't I, and tags after let's and imperatives

A question tag is the short question bolted onto the end of a statement: You are coming, aren't you? British English runs on them. They are how a speaker checks a fact without the rudeness of a direct question, how they fish for agreement, and how they soften an instruction into something that sounds optional when it is not.

The good news is that tags are built by a single mechanical rule. The bad news is that the handful of cases where English ignores that rule are among the most common tags you will ever say, so a learner who knows only the rule sounds confident and wrong. This page gives the rule first and then gives the exceptions the space they deserve.

The mirror rule

Two things happen at the end of the sentence. The auxiliary is repeated, and the polarity flips.

Positive statement, negative tag: She is late, isn't she?
Negative statement, positive tag: She is not late, is she?

That is the entire rule. Everything else on this page is either how to find the auxiliary or what to do when there is not one.

Two small points that learners get wrong even when they have the rule. First, the subject of a tag is always a pronoun, never the full noun: Your brother is late, isn't he?, not isn't your brother. Second, a negative tag is always contracted: isn't she, not is not she. The uncontracted form exists, but it puts the not after the pronoun (is she not?) and belongs to courtrooms and period drama.

Which auxiliary to use

If the statement already contains an auxiliary or a modal, reuse it. If it does not, the tag borrows do, does or did.

Statement	Tag	Why
You are* ready*	aren't you?	be is already there
He has* finished*	hasn't he?	reuse the perfect auxiliary
They will* come*	won't they?	reuse the modal
She can* swim*	can't she?	reuse the modal
You should* ask*	shouldn't you?	reuse the modal
He works* here*	doesn't he?	no auxiliary, so does
They left* early*	didn't they?	no auxiliary, so did
You did not* pay*	did you?	negative statement, positive
It has been* raining*	hasn't it?	tag the first auxiliary
You used to* smoke*	didn't you?	used to behaves as a past

The last one is worth pausing on. Used to has no auxiliary of its own, so it falls back on did, exactly like an ordinary past simple verb. See used to and would for the rest of that pattern, and modal verbs for the full modal set.

Must is the one modal that splits. When it means obligation, the tag mirrors it: You must go, mustn't you? When it means deduction (You must be tired), the tag mirrors the verb inside instead: You must be tired, aren't you?

The irregular cases

These are not footnotes. Between them they cover a large share of the tags an English speaker actually produces in a day.

aren't I

Amn't does not exist. English never built a negative contraction for am, so the tag after I am borrows the plural: I am late, aren't I? There is no argument to be had with this; it is simply the form. The strictly logical alternative, am I not?, is correct and sounds like you are addressing parliament.

The positive tag after a negative I am is entirely regular: I am not invited, am I?

After let's, the tag is shall we

Let's is a suggestion, not a statement, so there is nothing to mirror. The tag is fixed:

Let's start, shall we?
Let's not argue about it, shall we?

Note that this only applies to the contracted suggestion. If let us is a real imperative meaning "release us", it takes an imperative tag: Let us go, will you? You will not need that one often.

After an imperative, the tag is will you

An imperative has no auxiliary and no stated subject, so again there is nothing to mirror. The tag choice is about tone rather than grammar:

Close the door, will you? (neutral, slightly impatient)
Sit down, won't you? (warmer, an invitation)
Pass me the salt, would you? / could you? (politer)
Give me a hand, can you? (informal)

Negative imperatives break the mirror rule outright, because they take a positive tag anyway: Don't be late, will you? Not won't you, which would mean something close to the opposite.

There is, there are

There is not a real subject, but the tag keeps it regardless: There is a problem, isn't there? and There were no messages, were there? Do not substitute it or they.

Nobody, somebody, everyone

Indefinite people take they in the tag, even though the verb in the statement is singular: Somebody rang, didn't they? and Everyone signed it, didn't they? Indefinite things take it: Nothing happened, did it?

Negative words make a statement negative

This trips up nearly everyone. A sentence can be negative without containing not. If the subject or an adverb carries the negative, the statement counts as negative and takes a positive tag:

Nobody called, did they?
He never writes, does he?
She hardly ate anything, did she?
There is nothing left, is there?

Nobody, nothing, never, hardly, scarcely, rarely, seldom and few all do this. If a negative tag feels natural after one of them, you have made the mistake.

I think, I suppose, I believe

When the main clause is a reporting frame like I think, the tag attaches to the clause inside it, not to I think:

I think she is French, isn't she? (not don't I)
I don't think he will come, will he?

The second one is the interesting case: the negative has moved forward onto think, but it belongs logically to he will come, so the tag is positive. English calls this negative raising, and you do not need the name, only the habit.

Falling or rising: are you actually asking?

Here is the part that grammar books bury and speakers rely on. The same tag does two completely different jobs depending on what your voice does.

Falling intonation on the tag means you are not asking. You already know the answer and you want the other person to agree with you. It is small talk, shared ground, a nudge.

Lovely day, isn't it? (You can both see the sky.)
That was awful, wasn't it?

Rising intonation on the tag means you genuinely do not know and would like to be told.

You locked the door, didn't you? (Please say yes.)
This is the right platform, isn't it?

Same words on the page. In speech they are not remotely the same sentence, and a learner who tags everything with a rising tone comes across as permanently unsure of themselves. When you want agreement, let the tag fall.

Written English cannot show intonation, which is one reason tags read as more aggressive in a message than they sound out loud. You did send it, didn't you? in an email is an accusation. Say it aloud with a falling tone and it is barely a question at all.

Same-way tags

One more pattern worth recognising, because it sounds like a mistake and is not. A positive statement can take a positive tag:

So you are the new manager, are you?
You think that is funny, do you?

This is not the mirror rule failing. It signals interest, suspicion, sarcasm or a conclusion just drawn. It is common, it is native, and it is almost always mildly confrontational, so recognise it rather than reach for it.

Common mistakes

Ranked by how often learners actually make them.

Negative tag after a negative word. Nobody came, didn't they? is wrong. Nobody has already made the sentence negative, so the tag is positive: Nobody came, did they? Same for never, hardly and nothing.
Amn't I / am not I. The tag after I am is aren't I. Nothing else is available in ordinary English.
Mirroring an imperative. Close the door, don't you? is wrong. Imperatives take will you, won't you, would you or can you.
A noun in the tag. Your sister is coming, isn't your sister? should be isn't she. Tags take pronouns only.
Forgetting the do-support. You work here, aren't you? is wrong. The statement has no auxiliary, so the tag needs one: don't you.
Shall we after anything except let's. We should go, shall we? should be shouldn't we. Shall we belongs to let's and nowhere else.

Practice

Add the correct tag to each sentence. Answers are below.

You are coming with us, ___?
I am next, ___?
Nobody told her, ___?
Let's take a break, ___?
Turn the light off, ___?

Answers: 1. aren't you 2. aren't I 3. did they (nobody is already negative) 4. shall we (fixed after let's) 5. will you (imperative)

If you want the other half of English politeness machinery, the page on indirect questions covers the word-order flip that makes a direct question sound softer. And once you are reporting what somebody asked rather than asking it yourself, you are in reported speech.