diff between you may and you can

Question

Which one is more polite?

Imagine someone sends you email and ask you what time is good for you for a 15min phone interview. You wana tell the person to call call anytime during day; which one is more polite?

1-you may call me any time during day

2-you can call me any time during day

thank you

Comments

May sounds more polite.

http://oxforddictionaries.com/words/can-or-may

Answer 1

One can use both may and can to give permission with the former being more formal.