Use may when asking for permission. May I help you? not Can I help you?
The latter is asking if the person talking has the ability to help.
Might or may in your example can both be used but may sounds better. Might implies that there is a possibility of not helping or of helping, whereas might is
asking if it would be a possibility to help. I hope I've clarified that for you.

Simply put, may, is permission to, in some cases (yes, you may use that) or in some others, it is nearly interchangable.

May is often used in requesting on something.
E,g. May I borrow your CD?

It can also use in suggesting possible solution.
E.g. You may try this.

Might is often used in suggesting small possible solution.
E.g. It might work in your computer.

Might is the past tense of may.
Therefore, sometimes it depends on the tenses of the verb use in the sentence.

I might do it but you may not.

At most times, both words are interchangeable, although may is most commonly used these days.

nice

It may/might rain again today, may I borrow your umbrella? I think I may/might have left mine at work.

Might and may are commonly used when there is doubt about whether the subject is going to do/receive a certain action, or be something, in the future. It's also used to express uncertainty about what something or someone is right now or has done in the past.

Examples: He might be a good doctor. (This can either mean "He might be a good doctor [in the future]", or it can be talking about a doctor that exists, but we don't know if he is a good doctor or not.)

He might get hurt if he does that. (Future - we're not sure if he will get hurt if he does that, but it's possible.)

He might have already done it. (Past - we're not sure if he did it or not.)

I may not be able to come. (Future - I don't know if I'll be able to come or not.)

As for when you use which - as a native speaker, I never learned a rule for this, but you can read more about might and may here. (For one thing, "may" also implies permission - "You may kiss the bride.")

Might can refer to something you "might" do, like tonight I might go to the movies or I might read this really good book ive got. May is used similarly however is also used in legislation and gives permission and means someone may.....lodge a complaint if some component is met. Hope this helps.

i may do this party another day ok or i might do my home work now. did this help

Try this: http://www.englishgrammarsecrets.com/maymight/menu.php