"mi" o "yo" - what is the rule?

Question

What is the rule for choosing to use 'Yo' or 'Mi'?

Answer 1

mí and mi are different words. Did you mean mi (possessive adjective) or mí (objective case pronoun)?

personal pronouns

As you can see from this chart yo (I) is generally used as a subject pronoun and mí is used as an object of the preposition (me) or reflexive object of the preposition ( a mí mismo, para mí....myself)

Like most "rules" in Spanish, however, there are exceptions. There are a half a dozen prepositions that use yo rather than mí. (entre yo y tú).

And then there are the specifiic cases that must be treated individually, like the difference between a mí, también or Yo, también. We have previous threads detailing when each of those is used.

(Entre yo y tú) I know that it doesn't matter which way round in English, you and me or me and you but in Spanish they say Tú y yo. - kenwilliams, Feb 1, 2011