Question

FRENCH - Is there any difference in saying "Où es tu" and "Où t'es?"

Answer 1

"Où es-tu ?" is formal and "Où t'es ?" is familiar.

"Tu es où ?" is somewhere in between.

Answer 2

If the situation is formal, wouldn't vous be used instead? (t'es = TU es)

Answer 3

*Correction - I meant to reference "Es-tu" above, about using "etes-vous"?

Answer 4

Good point, but the tu/vous opposition mainly depends on the addressee.
The choice of formal/familiar speech depends on the speaker and the situation.

For example: a teacher is generally someone who uses formal speech / good grammar when addressing their students. It doesn't mean that the teacher will automatically say vous to the students.
As a teacher, I say tu to my students but I use formal language.
When I speak to my sister, I say tu also, but I can use familiar language.