Is it's me correct

Answer 1

According to proscriptive English grammar, both sides of a copula should be in the subjective case. In other words, "It's I" is formally correct, and "It's me" is incorrect.

However, most speakers do not speak according to the proscriptive grammar, and most speakers would find "It's I" to be unnecessarily formal and stilted. Likewise, most people would say "It's me," and would fail to notice anything wrong with that phrase upon hearing it or seeing it in writing.

Always consider your audience. If the reader hesitates on the awkward "It's I" -- even to admire your good grammar -- then they are distracted from the point you are trying to make. Following grammar rules will help you communicate effectively in most cases; but the ultimate goal is communication, not following rules.

Answer 2

The correct form is "It's me" when answering the phone or when identifying oneself.