May vs Might: Which One Do You Need?
Both express possibility. Might suggests it is less likely, and it is the one to use about things that did not happen.
It may rain later. It might have rained, but it did not.
The test that settles it
Ask whether the possibility is still open. If it has already closed, use might.
“we ___ go tomorrow” → still open, so either, with may sounding more likely.
“we ___ have drowned” → it did not happen, so might.
May: an open possibility, or permission
It presents something as genuinely possible. It also grants permission, which is its other main job.
The flight may be delayed.
You may begin.
She may already know.
Is the possibility still live, or are you giving permission? Then may.
Might: a remoter possibility, or one that has passed
Historically the past tense of may, now used for possibilities that feel less likely, and required for outcomes that never came about.
It might work, but I doubt it.
He might have been killed.
She said she might come.
Is it unlikely, or already ruled out? Then might.
Side by side
| May | Might |
|---|---|
| Open possibility, permission | Remoter possibility, or one now closed |
| More likely | Less likely |
| Present and future | Also reports past possibility |
| It may happen | It might have happened |
The exceptions
He may have drowned means we still do not know. He might have drowned, said after a rescue, means he did not.
Using may have for something that certainly did not happen is the error editors care about, because it changes the facts.
The old rule that can is about ability and may about permission is largely dead in speech. May I survives as the more formal request.
Where people get it wrong
| Incorrect | Correct | Why |
|---|---|---|
| If the rope had snapped he may have fallen. | If the rope had snapped he might have fallen. | It did not happen. |
| The parcel might arrive today or tomorrow. | The parcel may arrive today or tomorrow. | Genuinely open — though might is not wrong, just less confident. |
| May you pass the salt? | Could you pass the salt? | May asks permission of yourself, which is not the intention. |
| It may of been earlier. | It may have been earlier. | Of for have is a separate and common slip. |
Practice — choose the right word, then check yourself.
- The results ___ be published next week.
- Without the seatbelt she ___ have been injured.
- ___ I ask a question?
- It ___ work, though I am not hopeful.
- They ___ still be at home.
Show the answers
1. may 2. might 3. May 4. might 5. may
Frequently asked
Is the difference disappearing?
In speech, largely — the two are swapped freely. The counterfactual use of might is the part worth protecting, because it carries real information.
What about may in formal notices?
It often means permitted rather than possible: candidates may use a dictionary.
More words people confuse
