Grammar Guru — May, might

May is typically used in the present tense to indicate something that's likely to happen or to ask for permission. 

Might is typically used in the past tense to describe something that's unlikely to happen or situations that didn't take place.

Affirmative (+) form

May comes first in the verb phrase (after the subject and before another verb):

It may be possible for him to get home tonight.

May can’t be used with another modal verb:

This may hurt you.

Not: This may could hurt you. or This could may hurt you.

Negative (−) form

The negative form of may is may not. We don’t use don’t/doesn’t/didn’t with may:

We may not have enough information at the moment.

Not: We don’t may have enough information at the moment.

Warning:

We don’t use mayn’t as the contracted form of may not:

We may not yet know what is safe to eat.

Not: We mayn’t yet know what is safe to eat.

Question (?) form

Warning:

The subject and may change position to form questions. We don’t use do/does/did:

May we drop you at your hotel?

Not: Do we may drop you at your hotel?

May I leave the room, please?

Not: Do I may leave the room please?

May: uses

Permission

We use may to ask for, give and refuse permission. It is quite formal.

Can, could and may are all used to ask for permission. May is the most formal/polite and could is more formal and polite than can.

Possibility

We use may to refer to weak possibility in the present and future:

The economy may go up or down in the next year. (I think both are possible, the economy going up or the economy going down. I am not making either one a strong possibility.)

I think I may go to the doctor today and try to get some antibiotics. (I am not very sure yet if I will go to the doctor.)

General truths

We use may in formal writing, especially academic English, to describe things which the speaker thinks are generally true or possible. In this case, it is a more formal equivalent of can.

Compare

Accepting a different view or opinion

We often use may to accept a different view or opinion, especially with well, and/or followed by but:

One month may well be too long to go away on holiday.

I may be wrong but I am going to tell the police about it.

The couch may well cost more but it’s going to be different.

Affirmative (+) form

Might comes first in the verb phrase (after the subject and before another verb):

She might sell her house.

This might be true.

Not: That might can be true. or That can might be true.

Negative (−) form

The negative form of might is might not or mightn’t. We don’t use don’t/doesn’t/didn’t with might:

There might not be anyone in the house. (or There mightn’t be …)

Not: There doesn’t might be anyone in the house.

Question (?) form

The subject and might change position to form questions.

Warning:

We don’t use do/does/did:

Might this be the key?

Not: Does this might be the key?

Mightn’t this be the key?

Not: Doesn’t might this be the key?

We can use might and mightn’t in question tags, but they’re not very common:

That might not be a bad idea, might it?

That plant might do better by the window, mightn’t it?

Might: uses

Possibility

We use might most often to refer to weak possibility:

I might go to Japan for a month to study Japanese.

The dog might bark when we pass by the gate.

They might not like very hot food.

Permission

We use might to refer to permission. It is very formal and is not used very often:

Might I ask your name?

Might I interrupt you for a moment?

Warning:

The reply to these will not contain might:

A:

Might I ask your address?

B:

Yes. It’s 41 Ross Avenue.

A:

Might I ask you a question?

B:

Yes. Of course.

Not: Yes. You might.

Suggestions

We can use might to give advice or make a suggestion sound more polite or less direct, especially when used together with like, prefer or want:

[A waiter politely suggesting a dessert to a customer.]

You might like to try one of our wonderful desserts.

Criticism

We often use might have + -ed form to express disapproval or criticism:

You might have told me you weren’t coming home for dinner. (you didn’t tell me)

You might have tidied your room.

Might: reporting may

We use might as the past form of may in indirect reports:

‘That may not be true’, she said.

She said that it might not be true.

Might: typical error

We don’t use might for ability; we use can or could:

Although you can visit these places, if you are tired, you’re welcome to stay in the hotel.

Not: Although you might visit these places …

I could hear the noise of an engine.

Not: I might hear the noise of an engine.

We use could, may and might to express degrees of possibility. Many native speakers disagree on which one expresses more or less certainty.

Compare

The speaker also shows degree of certainty or uncertainty through intonation and stress. If the speaker stresses the modal verb, they are expressing more uncertainty than if they stress the main verb.