When should I use each of the following:

  • This may help.
  • This might help.

I always get confused about the use of may and might.


4 Answers 4


We use might to imply less possibility than when we use may.

Might is also the past tense of may.

If he had run faster, he might have won the race.

If he runs faster, he may win the race.

It is also considered a politer and more formal alternative to may.

Might I borrow your car?

There are other places that may and might may be used, but these are the ones that might be confusing.

  • I'm not certain I hear a difference in possibility in the phrases it might rain or it may rain. On the other hand, you may be right… or you might be wrong. See what I mean? Now, when we use must, that's different!
    – ghoppe
    Jan 11, 2011 at 23:15
  • 1
    A speaker most certainly can say "If the pilot had done such and such, the plane may not have crashed" if that speaker wants to state the level of certainty expressed by 'may'. It's done all the time in English. It's done despite the prescription saying you must use 'might'. It's done because that prescription is false. In your second example, we can also say, "If he runs faster, he might win the race". We use the modals with these epistemic meanings to express the level of certainty that we want to state. [to be continued]
    – Dan
    Apr 24, 2011 at 4:07
  • [continued]"If he had run faster, he would have/almost certainly would have/likely would have/may well/might well have won the race". "If he had run faster, perhaps he would have/maybe he would have won the race".
    – Dan
    Apr 24, 2011 at 4:09

It's really a toss-up, see http://topics.blogs.nytimes.com/2009/07/14/may-might-muddle/

If even the NYT has trouble using them "correctly" then I certainly won't bother too much. Didn't honestly know these subtleties (and they are subtle) myself.

Some more googling led me to http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv162.shtml So the BBC World Service seems to agree with me ;-)

Come to think of it, actually, I tend to hear/put an emphasis on "might" in this context, which clearly indicated this "(a little) less likely as may" meaning.


I agree that it's probably a toss-up in the examples you give.

However, in some uses the meaning of "may" as regards permission changes things a bit.

"You might say that" means it's an open question whether you'd say it or not.

"You may say that" means you have permission to do so.

Again, this isn't specifically germane to the examples you gave, but if I really really wanted to choose the one that is less likely to be misunderstood, I'd choose "might" as the common alternate meanings of that are less likely to show up in similar contexts.

But it's really splitting hairs at that point as you're unlikely to be misunderstood in either case.


The difference between the two sentences is the degree in which you are confident it would help. In the first case, you are quite confident, but you wouldn't say it's a 100% certainty. In the second case, you are not so sure that it would help.

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