Modal verbs – may/might

The modal verbs may/might are the primary pair used to show how likely something is to happen. If you read an introduction to modal verbs, you will remember that modal pairs often have two relationships: one based on time and one based on probability/likelihood. This is also true of the may/might pair. Let’s look at how we can use them:

(Future) Possibility + may/might

When we use may/might, we are often talking about the possibility of something happening. In this case, may is more probable than might. For example, let’s compare the following two sentences:

  • It may rain tonight.
  • It might rain tonight.

This pair of examples shows us that, at least grammatically, may and might are interchangeable. So what is the difference? In the first sentence there is a high possibility of rain. In the second sentence, the possibility of rain is lower. If you were to order sentences like these in terms of possibility, it would look something like this:

  • It will rain tonight. – (almost) guaranteed
  • It may rain tonight. – somewhat likely
  • It might rain tonight. – somewhat unlikely
  • It will not rain tonight. – (almost) impossible

There are no set percentages that one could use as equivalents for may and might. What makes them different is how likely something is to happen. In this case It may rain shows that there is a possibility and it is somewhat likely to happen. It might rain shows that the possibility exists but it is somewhat unlikely to happen.

May/might + Permission

May can also be used to ask for permission. For example:

  • May I go to the toilet? Yes, you may.

In this sentence the speaker is asking someone to be allowed to do something. The answer uses the modal verb to tell the person that they can do it.

While might can be used for permission, it is more formal than may. For example:

  • Might I go to the toilet?

This question is more formal than the previous request for permission. However, it is very important to note that some dialects of English no longer use might in this way and in those that still use it, its use becoming more rare.

Typical Occurrences

May/might are also used to talk about things that usual occur in a situation. This use of the modal pair is often used in public announcements and health information. An example of this use is:

  • Drivers under the influence of alcohol may have a reduced reaction time.

This use is related to possibility. It states that usually in a situation, this thing happens. As this does not happen all the time, you need to use a modal verb to show that there is a possibility. In this case the outcome is likely, so may is used. If it were less likely, you could use might instead. For example:

  • Patients taking drug A might experience cramps.


May can also be used for a speaker/writer to express their wish for something to come true. This could be for themselves or for someone or something else. For example:

  • May all your wishes come true.
  • May fortune favour you!


May and might along with the present perfect can also be used to speculate about something that was possible in the past but did not happen. For example:

  • It may have worked eventually but we gave up.
  • The reason she was a naughty child might have been because of me.

For these speculations about the past, may have and might have are generally interchangeable in use; the difference is meaning is due to how certain you are. As before, may is more certain than might.

Possibility in the past

May have and might have can also be used to show that there was the possibility of something happening in the past but it did not (for some reason). These can usually be used interchangeably but the user may use might have instead of may have to show more uncertainty.

  • It may have worked eventually but we gave up.
  • It might have been my fault.

Want to learn more about modal verbs? You can find a guide to all the modal verbs here: introduction to modal verbs. You can also learn more about other English language information on my Learning English page.

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