Dana's right. They are different in politeness and kindness. For example: A child and his mom are walking along the street in hot summer. Child: "Mom, can I have an ice-cream?" Mom: "May I ...".(This means "You should say 'May I have an ice-cream'") Child: "May I have an ice-cream?"

"may" and "can" are usually treated the same way in English, but the strict definition is: Can - To be able to OR to be allowed/permitted to May - To be allowed/permitted to When you ask "May I take off for a few?" you are asking permission When you ask "Can I take off for a few?" you are asking if you physically are able to do so, if it is possible, or if you have permission. Again: They are typically used interchangably for permission. When asking if you can physically do something (if it is possible) then "Can" is used exclusively.

When you use "may" instead of "can," it is more formal and polite, but nowadays people say "can" instead of "may" for most things.