It's the same question. The second cuestion is for an informal conversation: "de donde eres 'tu'? but, "de donde es 'usted'? it's used in formal conversation.

The only difference is "de donde es usted?" is more formal. You use this sentence when you are trying to know more of a person and there is no confidence between you and that person. Now, in a relaxed situation, you can ask "de donde eres?". In this case, is less formal, and it's used between colleagues, friends.

"Usted" is the polite way for unknown people, elderly people or a higher rank person. The second one, "tú", is the usual way for acquaintances, friends or people you have been introduced (relaxed ambiance)

La formalidad, ya que "eres" es la conjugación del indicativo presente para TU. Si hay cierta distancia con tu interlocutor es conveniente decir "¿De dónde es usted?" y si es una ambiente más informal está bien decir "¿De dónde eres tú? o simplemente de ¿De dónde eres?. En sintesis la diferencia es el grado de formalidad con la que quieres realizar la pregunta. Saludos !

de dónde eres? is more informal, whereas de dónde es usted ? is a very formal way Both has the same meaning.