Key Difference: May or might, both are the way of expressing possibility. May is to have the permission and might is to make a possibility less likely or a request for permission more politely.

It has always been confusing to differentiate between ‘may’ and ‘might.’

So for understanding the usage of words ‘May’ and ‘Might,’ let us consider the following examples:

• You may go home now.
• She might win if she tries hard.
• He may be here, I don’t know.
• They might come if you offered them a meal.
• May you live a long and happy life.
• Might I speak to you for a few minutes, please?
• If it’s not too cold, I might go to the beach.
• I may go to the beach tomorrow.

The above examples gives a very clear idea that may is used to express a possibility in the present or future and might is used instead of ‘may’ i.e. for the past tense.

May is usually used to ask for permission, whereas might is usually used to suggest doubt. For example: May I be late? I might be late. The first sentence is used to ask for permission to be late. The second sentence states that the user is unsure whether he will be late. He is merely suggesting that he could be late.

Basically, they have a minor difference but may is usually not used in the past tense, whereas might usually is. Furthermore, might is quite more formal to the ear as compared to may. It is more appropriate in the academic or official writing. In other situations, both are used the same way. 

May is to express the possibility in informal manner without any dependence. It has been stated that ‘may’ is used when the action is positive or is possible. Might is applied when the action is not going to be positive or is not possible.

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